As filed with the Securities and Exchange Commission on August 24, 2001.
                                                           Registration No. 333-
================================================================================
                      SECURITIES AND EXCHANGE COMMISSION
                             Washington, DC 20549

                                --------------
                                   FORM S-3
                            REGISTRATION STATEMENT
                                     UNDER
                          THE SECURITIES ACT OF 1933

                                --------------

 AmerisourceBergen Corporation            Delaware               23-3079390
AmeriSource Health Corporation            Delaware               23-2546940
   AmeriSource Corporation                Delaware               23-2353106
(Exact name of Registrant as (State or Other Jurisdiction of  (I.R.S. Employer
  specified in its charter)  Incorporation or Organization)  Identification No.)

                                --------------

                          1300 Morris Drive, Suite 100
                           Chesterbrook, PA 19087-5594
   (Address, Including Zip Code, and Telephone Number, Including Area Code, of
                    Registrant's Principal Executive Offices)

                                --------------

                            William D. Sprague, Esq.
                         Vice President and Secretary
                          AmerisourceBergen Corporation
                          1300 Morris Drive, Suite 100
                           Chesterbrook, PA 19087-5594
                                 (610) 727-7000
     (Name, address including zip code, and telephone number, including area
                          code, of agent for service)

                                --------------
                                With Copies to:

                            Craig L. Godshall, Esq.
                                    Dechert
                           4000 Bell Atlantic Tower
                               1717 Arch Street
                          Philadelphia, PA 19103-2793
                                (215) 994-4000

                                --------------
     Approximate date of commencement of proposed sale to the public: [_]

     If any of the securities being registered on this Form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, other than securities being offered only in connection with dividend or
interest reinvestment plans, check the following box. [X]

     If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering. [_]

     If this form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. [_]

     If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box. [_]

                                --------------

                        CALCULATION OF REGISTRATION FEE



============================================================================================================================
                                                            Proposed Maximum        Proposed Maximum
        Title of Each Class of            Amount to be      Aggregate Price        Aggregate Offering         Amount of
      Securities to be Registered          Registered         Per Unit (1)               Price            Registration Fee
----------------------------------------------------------------------------------------------------------------------------
                                                                                              
5% Convertible Subordinated Notes Due    $300,000,000             100%                $300,000,000           $75,000(1)
     December 1, 2007 of
     AmeriSource Health Corporation
     and AmerisourceBergen
     Corporation
============================================================================================================================
Common Stock of AmerisourceBergen           5,663,730 (2)          --                      --                  -- (3)
     Corporation, par value $.01
     per share
============================================================================================================================
Guarantee by AmeriSource Corporation            --                 --                      --                  -- (4)
============================================================================================================================


(1) Pursuant to Rule 429 under the Securities Act, this Registration Statement
contains a combined prospectus that relates to $300,000,000 of 5% Convertible
Subordinated Notes due December 1, 2007 issued by AmeriSource Health Corporation
and previously registered on Registration Statement No. 333-56538 on Form S-3,
filed by AmeriSource Health Corporation and AmeriSource Corporation on March 5,
2001, for which notes AmerisourceBergen Corporation has assumed the obligations
of AmeriSource Health Corporation. A registration fee of $75,000 was previously
paid with the prior Registration Statement.
(2) Plus such additional indeterminate number of shares as may become issuable
upon conversion of the 5% Convertible Subordinated Notes due 2007 registered
hereunder by means of adjustment to the conversion price applicable thereto.
(3) The shares of common stock registered hereunder are issuable upon conversion
of the 5% Convertible Subordinated Notes due 2007 registered hereunder. Pursuant
to Rule 457(i) under the Securities Act, there is no filing fee with respect to
the shares of common stock issuable upon conversion.
(4) Pursuant to Rule 457(n) under the Securities Act, there is no filing fee
with respect to the Subsidiary Guarantee.

                                --------------
The Registrants hereby amend this Registration Statement on such date or dates
as may be necessary to delay its effective date until the Registrants shall file
a further amendment which specifically states that this Registration Statement
shall thereafter become effective in accordance with Section 8(a) of the
Securities Act of 1933 or until this Registration Statement shall become
effective on such date as the Commission, acting pursuant to said Section 8(a),
shall determine.
================================================================================


                                     LOGO

                         AMERISOURCEBERGEN CORPORATION

                        AMERISOURCE HEALTH CORPORATION

                       $300,000,000 Principal Amount of
            5% Convertible Subordinated Notes Due December 2007 and
    5,663,730 Shares of Common Stock Issuable Upon Conversion of the Notes

     AmeriSource Health Corporation issued the 5% Convertible Subordinated Notes
in a private placement in December 2000.  On August __, 2001, AmeriSource Health
Corporation and Bergen Brunswig Corporation completed a business combination in
which AmeriSource and Bergen became wholly-owned subsidiaries of a new parent
company named AmerisourceBergen Corporation.  In the merger, each outstanding
share of AmeriSource common stock was converted into one share of
AmerisourceBergen common stock and each share of Bergen common stock was
converted into 0.37 shares of AmerisourceBergen common stock.  As a result, the
notes are convertible into shares of AmerisourceBergen common stock.

     This prospectus will be used by selling securityholders to resell their
notes and the common stock issuable upon conversion of their notes at market
prices prevailing at the time of sale, fixed or varying prices determined at the
time of sale, or at negotiated prices. The selling securityholders may sell the
notes or the common stock directly to purchasers or through underwriters,
broker-dealers or agents, who may receive compensation in the form of discounts
or commissions. We will not receive any proceeds from this offering.

     The notes are convertible into shares of AmerisourceBergen's common stock
at any time before their maturity or their prior redemption or repurchase by
AmeriSource. The notes will mature on December 1, 2007. The conversion rate is
18.8791 shares for each $1,000 principal amount of notes, subject to adjustment
in certain circumstances. This is equivalent to a conversion price of
approximately $52.97 per share.

     AmerisourceBergen or AmeriSource will pay interest on the notes on June 1
and December 1 of each year.  The first interest payment was made on June 1,
2001. The notes are subordinated in right of payment to all of our existing and
future senior debt.  The notes are unconditionally guaranteed on a subordinated
basis by AmerisourceBergen's indirect wholly-owned subsidiary, AmeriSource
Corporation. In connection with the merger, AmerisourceBergen became a co-
obligor with AmeriSource under the 5% Convertible Subordinated Notes.  The notes
will be issued only in denominations of $1,000 and integral multiples of $1,000.

     On or after December 3, 2004, AmeriSource has the option to redeem all or a
portion of the notes that have not been previously converted at the redemption
prices set forth in this prospectus. A holder has the option, subject to certain
conditions, to require AmeriSource to repurchase any notes held by it in the
event of a "Change in Control," as described in this prospectus, at a price
equal to 100% of the principal amount of the notes plus accrued interest to the
date of repurchase.  The merger, in which AmeriSource and Bergen became
subsidiaries of AmerisourceBergen, did not constitute a Change in Control.

         We have not applied for listing of the notes on any securities exchange
or for quotation through any automated quotation system. The notes are eligible
for trading in the Private Offerings, Resale and Trading Through Automated
Linkages (PORTAL) market of the National Association of Securities Dealers, Inc.
AmerisourceBergen common stock is traded on the New York Stock Exchange under
the symbol "ABC". The closing price of the common stock on the New York Stock
Exchange on August __, 2001 was $____ per share.

                                ---------------
         The securities offered hereby involve a high degree of risk. See "Risk
Factors" beginning on page 9.

                                ---------------
         Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved of these securities or determined if this
prospectus is truthful or complete. Any representation to the contrary is a
criminal offense.


                    This prospectus is dated August __, 2001




         You should rely only on the information contained in or incorporated by
reference in this prospectus. We have not authorized anyone to provide you with
different information. We are not making an offer of these securities in any
state where the offer is not permitted. You should not assume that the
information contained in or incorporated by reference in this prospectus is
accurate as of any date other than the date on the front of this prospectus.


                               TABLE OF CONTENTS



                                                                       Page

                                                                  
WHERE YOU CAN FIND MORE INFORMATION..................................   2
FORWARD-LOOKING STATEMENTS...........................................   3
SUMMARY..............................................................   5
RISK FACTORS.........................................................   9
USE OF PROCEEDS......................................................  14
RATIO OF EARNINGS TO FIXED CHARGES...................................  15
DESCRIPTION OF THE NOTES.............................................  15
CERTAIN UNITED STATES FEDERAL INCOME AND ESTATE TAX CONSEQUENCES.....  30
DESCRIPTION OF CAPITAL STOCK.........................................  34
SELLING SECURITYHOLDERS..............................................  36
PLAN OF DISTRIBUTION.................................................  43
LEGAL MATTERS........................................................  44
EXPERTS..............................................................  44




                       WHERE YOU CAN FIND MORE INFORMATION

         AmerisourceBergen files, and AmeriSource and Bergen have filed,
reports, proxy statements, information statements and other information with the
Securities and Exchange Commission. You may read and copy this information, for
a copying fee, at the Commission's Public Reference Room at 450 Fifth Street,
N.W., Washington, D.C. 20549, and at the regional offices of the Commission
located at Citicorp Center, 500 West Madison Street, Suite 1400, Chicago,
Illinois 60661 and Seven World Trade Center, Suite 1300, New York, New York
10048. Please call the Commission at 1-800-SEC-0330 for more information on its
public reference rooms. Commission filings are also available to the public from
commercial document retrieval services and at the web site maintained by the
Commission at http://www.sec.gov.

         AmerisourceBergen common stock is traded on the New York Stock Exchange
and, therefore, the information AmerisourceBergen files with the Commission may
also be inspected at the offices of the New York Stock Exchange, located at 20
Broad Street, New York, NY 10005.

         The Commission allows us to "incorporate by reference" information into
this prospectus, which means that we can disclose important information to you
by referring to another document filed separately with the Commission. The
information incorporated by reference is deemed to be part of this prospectus,
except for information superseded by this prospectus. This prospectus
incorporates by reference the documents set forth below that AmeriSource, Bergen
and AmerisourceBergen have previously filed with the Commission. These documents
contain important information about AmeriSource, Bergen and AmerisourceBergen.

         .     AmeriSource's Quarterly Report on Form 10-Q for the quarter ended
               June 30, 2001;

         .     AmeriSource's Quarterly Report on Form 10-Q for the quarter ended
               March 31, 2001;

         .     AmeriSource's Quarterly Report on Form 10-Q for the quarter ended
               December 31, 2000;

         .     AmeriSource's Annual Report on Form 10-K for the year ended
               September 30, 2000;

         .     AmeriSource's Current Report on Form 8-K dated July 30, 2001;

                                       2


         .     AmeriSource's Current Report on Form 8-K dated March 27, 2001;

         .     AmeriSource's Current Report on Form 8-K dated March 19, 2001;

         .     AmeriSource's Current Report on Form 8-K dated December 14, 2000;

         .     AmeriSource's Current Report on Form 8-K dated December 7, 2000;

         .     AmeriSource's Current Report on Form 8-K dated December 4, 2000;

         .     AmeriSource's Proxy Statement on Schedule 14A dated January 26,
               2001;

         .     Bergen's Quarterly Report on Form 10-Q for the quarter ended June
               30, 2001;

         .     Bergen's Quarterly Report on Form 10-Q for the quarter ended
               March 31, 2001;

         .     Bergen's Quarterly Report on Form 10-Q for the quarter ended
               December 31, 2000;

         .     Bergen's Current Report on Form 8-K dated July 30, 2001;

         .     Bergen's Current Report on Form 8-K dated July 18, 2001;

         .     Bergen's Current Report on Form 8-K dated March 19, 2001;

         .     Bergen's Annual Report on Form 10-K for the year ended September
               30, 2000;

         .     Bergen's Proxy Statement on Schedule 14A dated January 12, 2001;

         .     AmerisourceBergen's Registration Statement on Form S-4 dated May
               23, 2001, including the final proxy statement-prospectus
               contained therein at the time of effectiveness;

         .     AmerisourceBergen's Current Report on Form 8-K dated August 1,
               2001.

         This prospectus also incorporates by reference all documents that may
be filed by AmerisourceBergen, AmeriSource or Bergen with the Commission under
Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act after the date
of this prospectus and prior to the termination of this offering.

         If you are a stockholder, we may have sent you some of the documents
incorporated by reference, but you can obtain any of them through us or the
Commission. Documents incorporated by reference are available from us without
charge, except exhibits, unless we have specifically incorporated by reference
an exhibit into a document that this prospectus incorporates. Stockholders may
obtain documents incorporated by reference into this prospectus by requesting
them in writing or by telephone from:

         AmerisourceBergen Corporation or AmeriSource Corporation, Attention:
General Counsel, 1300 Morris Drive, Suite 100, Chesterbrook, Pennsylvania 19087-
5594 Telephone: (610) 727-7000.

                          FORWARD-LOOKING STATEMENTS

         This prospectus includes forward-looking statements within the meaning
of the Private Securities Litigation Reform Act of 1995. These statements relate
to analyses and other information that are based on forecasts of future results
and estimates of amounts not yet determinable. These statements also relate to
our future prospects, developments and business strategies. The statements
contained in this prospectus that are not statements of historical fact may
include forward-looking statements that involve a number of risks and
uncertainties.

         We have used the words "anticipate," "believe," "could," "estimate,"
"expect," "intend," "may," "plan," "predict," "project," "will" and similar
terms and phrases, including references to assumptions, in this prospectus to
identify forward-looking statements. These forward-looking statements are made
based on our management's expectations and beliefs concerning future events
affecting us and are subject to uncertainties and factors relating to our
operations and business environment, all of which are difficult to predict and
many of which are beyond our control, that could cause our actual results to
differ materially from those matters expressed in or implied by these forward-
looking statements. The following factors are among those that may cause actual
results to differ materially from our forward-looking statements:

                                       3


     .        acquisitions and dispositions;

     .        changes in general economic, business and industry conditions;

     .        changes in pharmaceutical manufacturer pricing and distribution
              policies;

     .        changes in political and social conditions and local regulations;

     .        significant litigation;

     .        changes in sales mix;

     .        competition;

     .        disruptions of established supply channels;

     .        degree of acceptance of new products;

     .        difficulty of forecasting sales at various times in various
              markets;

     .        the availability, terms and deployment of capital; and

     .        the other factors discussed below under the heading "Risk Factors"
              and elsewhere in this prospectus.

     All of our forward-looking statements should be considered in light of
these factors and other factors set forth in "Risk Factors" and elsewhere in
this prospectus or incorporated by reference in this prospectus. We undertake no
obligation to update our forward-looking statements or risk factors to reflect
new information, future events or otherwise.

                                       4


                                    SUMMARY

         The following summary should be read in conjunction with, and is
qualified in its entirety by, the more detailed information appearing elsewhere
in this prospectus. Unless the context otherwise requires:

         .     "we," "us," "AmerisourceBergen" and "the Company" refer to
               AmerisourceBergen Corporation and its subsidiaries on a
               consolidated basis.

         .     "AmeriSource" refers to AmeriSource Health Corporation and its
               subsidiaries on a consolidated basis.

         .     "Bergen" refers to Bergen Brunswig Corporation and its
               subsidiaries on a consolidated basis.



                               AmerisourceBergen

               We are a leading national wholesale distributor of pharmaceutical
products and related healthcare services and solutions with pro forma operating
revenue (excluding bulk shipments) of approximately $32 billion, pro forma
adjusted earnings before interest expense, taxes, depreciation and amortization
of approximately $620 million and pro forma operating income of approximately
$462 million for the twelve-month period ended March 31, 2001.

               On August __, 2001, AmeriSource and Bergen completed the merger.
AmeriSource and Bergen announced their intent to combine in a merger-of-equals
to form our company. The merger will enable us to significantly enhance our
competitive position with:

         .     enhanced scale of operations;

         .     operating and administrative cost savings;

         .     improved purchasing efficiencies;

         .     improved working capital management; and

         .     broadened product offering.

               As a result of the merger, we expect to achieve estimated cost
savings of approximately $125 million per year by the end of the third year
following the consummation of the merger from, among other things, the
consolidation of distribution facilities and related working capital
improvements, the elimination of duplicative administrative functions and
generic inventory purchasing efficiencies. We also expect to benefit from lower
financing costs as a result of the combination.

               Our greater scale of operations enhances our competitive position
in our core wholesale pharmaceutical distribution business through improved
access to capital, enhanced purchasing efficiencies and a broader service
offering to our customers. We have several initiatives to provide additional
value-added services to our customers including pharmaceutical packaging,
management information and consulting services and specialty pharmaceutical
product distribution and services.

               Our businesses operate in two segments. The first segment,
pharmaceutical distribution, includes our core wholesale pharmaceutical drug
distribution business, ASD Specialty Healthcare--our pharmaceutical alternate
site distribution business and American Health Packaging--our pharmaceutical
repackaging business. Pharmaceutical distribution also includes a number of
smaller specialty units in areas such as management reimbursement consulting
services and third party logistics services for pharmaceutical manufacturers.
Our second operating segment is PharMerica, a leading national provider of
institutional pharmacy services in long-term care and alternate site settings.
PharMerica also provides mail-order pharmacy services to chronically and
catastrophically ill patients under workers' compensation programs.

                                       5


               We are attractively positioned in the market as the only national
wholesale pharmaceutical distributor exclusively focused on pharmaceutical
product distribution, services and solutions. We serve the following major
market segments:

         .     acute care hospitals and health systems;

         .     independent retail pharmacies;

         .     the alternate site market; and

         .     national and regional retail pharmacy chains.


               We currently serve customers through a geographically diverse
network of distribution centers in the United States. We are typically the
primary source of supply for pharmaceutical and related products to our
customers. We offer a broad range of solutions to our customers and suppliers
designed to enhance the efficiency and effectiveness of their operations,
allowing them to improve the delivery of healthcare to patients and consumers
and lower overall costs in the pharmaceutical supply chain.

               In the alternate site market, we supply pharmaceuticals and other
related products and services to the oncology, nephrology, vaccine, plasma and
other specialty healthcare markets. We serve a continuum of customers including
physicians' offices and clinics, skilled nursing facilities, mail-order
facilities, assisted living centers and chronically ill patients. We also
provide plasma products to acute care hospitals.

               Our principal executive offices are located at 1300 Morris Drive,
Suite 100, Chesterbrook, Pennsylvania 19087-5594 and our western management
center is located at 4000 Metropolitan Drive, Orange, California 92868-3510. Our
telephone number is (610) 727-7000. AmeriSource's website is http://www.
amerisource.com and Bergen's website is http://www.bergenbrunswig.com. Any
Internet addresses provided in this prospectus are for information purposes
only and are not intended to be hyperlinks. Accordingly, no information in
any of these Internet addresses is included herein.

                                       6


                                 The Offering

                                                             
Securities offered.........................................     $300,000,000 aggregate principal amount of 5% Convertible
                                                                Subordinated Notes and 5,663,730 shares of common stock
                                                                issuable upon conversion of the notes.

Interest...................................................     We will pay interest on the notes semi-annually on June 1
                                                                and December 1 of each year, commencing June 1, 2001.

Guarantor..................................................     Our subsidiary, AmeriSource Corporation, has fully and
                                                                unconditionally guaranteed the notes on a subordinated
                                                                basis.

Conversion.................................................     You may convert each note into common stock at any time on
                                                                or before December 1, 2007 at a conversion rate of 18.8791
                                                                shares of common stock per $1,000 principal amount of notes
                                                                which is equivalent to a conversion price of approximately
                                                                $52.97 per share, subject to adjustment in certain events.

Subordination..............................................     The notes are subordinated to our present and future senior
                                                                indebtedness. The notes are also effectively subordinated
                                                                in right of payment to all indebtedness and other
                                                                liabilities of our subsidiaries, other than AmeriSource.
                                                                AmeriSource Corporation's obligations under the subsidiary
                                                                guarantee is subordinated to all existing and future senior
                                                                indebtedness of AmeriSource Corporation. Neither we nor our
                                                                subsidiaries are limited from incurring additional debt,
                                                                including senior indebtedness, under the indenture.

Optional redemption by AmeriSource.........................     AmeriSource may redeem the notes, at its option, in whole or
                                                                in part, on or after December 3, 2004, at the redemption
                                                                prices set forth in this prospectus plus accrued and unpaid
                                                                interest.

Repurchase at option of holders upon change in a control...     If a change in control of AmerisourceBergen Corporation
                                                                occurs, each note holder will have the right, subject to
                                                                certain conditions and restrictions, to require us to
                                                                repurchase the notes held by them at 100% of their
                                                                principal amount, plus accrued interest to the repurchase
                                                                date. We may choose to pay this purchase price in cash or
                                                                in shares of our common stock valued at 95% of the average
                                                                closing sales prices for the five trading days immediately
                                                                preceding and including the third day prior to the
                                                                repurchase date.

Use of proceeds............................................     We will not receive any of the proceeds from the sale by
                                                                any selling securityholder of the notes or the underlying
                                                                common stock.


                                       7


                                 Risk Factors

         An investment in the notes involves risks. Before you invest, you
should consider the risk factors described on pages 9 through 13 of this
prospectus.

                                       8


                                 RISK FACTORS

         An investment in our notes or our common stock involves a high degree
of risk. You should carefully consider the following risk factors and other
information contained in and incorporated by reference into this prospectus
before investing in our notes or our common stock. The trading price of our
notes and our common stock could decline due to any of these risks, and you may
lose all or part of your investment.

Our substantial indebtedness could adversely affect our financial health and
adversely impact our ability to repay the notes.

         We are highly leveraged and we and our subsidiaries will be permitted
to incur substantial additional indebtedness in the future. See "Description of
Notes."

         Our substantial indebtedness could have important consequences to you.
For example, it could:

         .     make it more difficult for us to satisfy our obligations with
               respect to the notes;

         .     increase our vulnerability to general adverse economic and
               industry conditions;

         .     limit our ability to obtain additional financing to fund future
               working capital, capital expenditures, and other general
               corporate requirements, or to carry out other aspects of our
               business plan;

         .     require us to dedicate a substantial portion of our cash flow
               from operations to the payment of principal of, and interest on,
               our indebtedness, thereby reducing the availability of such cash
               flow to fund working capital, capital expenditures, or other
               general corporate purposes, or to carry out other aspects of our
               business plan;

         .     limit our flexibility in planning for, or reacting to, changes in
               our business and the industry; and

         .     place us at a competitive disadvantage compared to our
               competitors that have less debt.

To service our indebtedness, we will require a significant amount of cash. Our
ability to generate cash depends on many factors beyond our control.

         Our ability to make payments on and to refinance our indebtedness,
including the notes, and to fund planned capital expenditures and efforts will
depend on our ability to generate cash in the future. This, to a certain extent,
is subject to general economic, financial, competitive, legislative, regulatory
and other factors that are beyond our control.

         Based on our current level of operations and anticipated cost savings
and operating improvements, we believe that cash flow from operations and
available cash, together with available borrowings under our new credit
facility, will be adequate to meet our future liquidity needs for at least the
next few years. We may, however, need to refinance all or a portion of the
principal amount of the notes on or prior to maturity.

         We cannot assure you, however, that our business will generate
sufficient cash flow from operations, that anticipated revenue growth and
operating improvements will be realized or that future borrowings will be
available in an amount sufficient to enable us to service our indebtedness,
including these notes, or to fund our other liquidity needs. In addition, we
cannot assure you that we will be able to refinance any of our indebtedness,
including these notes, on commercially reasonable terms or at all.

The market price of our common stock and the notes may fluctuate significantly,
which may result in losses for investors.

         The stock market and the price of our common stock may be subject to
volatile fluctuations based on general economic and market conditions, industry
trends and company performance. The market price for our common stock may also
be affected by our ability to meet analysts' expectations. Failure to meet such
expectations, even slightly, could have an adverse effect on the market price of
our common stock. In the past, following periods of volatility in the market
price

                                       9


of a company's securities, securities class action litigation has often been
instituted against such a company. If similar litigation were instituted against
us, it could result in substantial costs and diversion of our management's
attention and resources, which could have an adverse effect on our business.
Because of the volatility, we may fail to meet the expectations of our
stockholders or of securities analysts at some time in the future, and our stock
price, and therefore the price our notes, could decline as a result.

AmerisourceBergen and AmeriSource are holding companies and rely on dividends
from their subsidiaries to make payments on the Notes

         Substantially all of our properties are owned by, and substantially all
of our operations are conducted through, our subsidiaries. As a result, we
depend on dividends and other payments from our subsidiaries to satisfy our
financial obligations and make payments to our investors. The ability of our
subsidiaries to pay dividends and make other payments to us is subject to
certain restrictions under the terms of our debt agreements. See "Description of
the Notes--Subordination". In addition, the ability of a subsidiary to pay
dividends to us will be limited by applicable law. In the event of bankruptcy
proceedings affecting a subsidiary, to the extent we are recognized as a
creditor of that subsidiary, our claims would still be subordinate to any
security interest in or other lien on any assets of that subsidiary and to any
of its debt and other obligations that are senior to the payment of the notes.

The notes are subordinated to other debt and not secured by any of our assets,
and we may be unable to repay our obligations under the notes.

         The notes will be unsecured and subordinated in right of payment to all
of our existing and future senior debt and the obligations of AmeriSource
Corporation under the subsidiary guarantee will be unsecured and subordinated in
right of payment to all of the existing and future senior debt of AmeriSource
Corporation. Because the notes and the obligations of AmeriSource Corporation
under the subsidiary guarantee are subordinate to our and AmeriSource
Corporation's senior debt, if we experience:

         .    bankruptcy, liquidation or reorganization;

         .    an acceleration of the notes due to an event of default under the
              indenture; or

         .    other specified events, we and AmeriSource Corporation will be
              permitted to make payments on the notes and the subsidiary
              guarantee, as the case may be, only after we have satisfied all of
              our senior debt obligations. Therefore, neither we nor AmeriSource
              Corporation may have sufficient assets remaining to pay amounts
              due on any or all of the notes.

         The indenture for the notes does not limit our ability, or that of any
of our presently existing or future subsidiaries, to incur senior debt, other
indebtedness and other liabilities. We and AmeriSource Corporation may have
difficulty paying our obligations under the notes or the subsidiary guarantee,
as the case may be, if we, or AmeriSource Corporation, incur additional
indebtedness or other liabilities. From time to time we and our subsidiaries may
incur additional indebtedness, including senior debt, which could adversely
affect our ability to pay our obligations under the notes.

The subsidiary guarantee may be unenforceable.

         Although laws differ among various jurisdictions, a court could, under
fraudulent conveyance laws, further subordinate or avoid the subsidiary
guarantee if it found that the subsidiary guarantee was incurred with actual
intent to hinder, delay or defraud creditors or that AmeriSource Corporation did
not receive fair consideration or reasonably equivalent value for the subsidiary
guarantee and that AmeriSource Corporation was any of the following:

         .    insolvent or was rendered insolvent because of the subsidiary
              guarantee;

         .    engaged in a business or transaction for which its remaining
              assets constituted unreasonably small capital; or

         .    intended to incur, or believed that it would incur, debts beyond
              its ability to pay at maturity.

                                       10


     If a court voided the subsidiary guarantee as the result of a fraudulent
conveyance, or held it unenforceable for any other reason, holders of the notes
would cease to have a claim against AmeriSource Corporation based on the
subsidiary guarantee and would be solely creditors of AmeriSource and
AmerisourceBergen.

The assumption of the notes by AmerisourceBergen may be unenforceable.

     Although laws differ among various jurisdictions, a court could, under
fraudulent conveyance laws, further subordinate or avoid the assumption of the
notes by AmerisourceBergen if it found that the assumption was incurred with
actual intent to hinder, delay or defraud creditors or that AmerisourceBergen
did not receive fair consideration or reasonably equivalent value for the
assumption and that AmerisourceBergen was any of the following:

 .  insolvent or was rendered insolvent because of the assumption;
 .  engaged in a business or transaction for which its remaining assets
   constituted unreasonably small capital; or
 .  intended to incur, or believed that it would incur, debts beyond its ability
   to pay at maturity.

     If a court voided the assumption as the result of a fraudulent conveyance,
or held it unenforceable for any other reason, holders of the notes would cease
to have a claim against AmerisourceBergen based on the assumption and would be
solely creditors of AmeriSource.

We may be unable to repay or repurchase the notes.

     At maturity, the entire outstanding principal amount of the notes will
become due and payable. In addition, if we experience a change in control, as
defined in "Description of the Notes--Repurchase at Option of Holders Upon a
Change in Control", each holder of the notes may require us to repurchase all or
a portion of that holder's notes. At maturity or if a change in control occurs,
we may not have sufficient funds or may be unable to arrange for additional
financing to pay the principal amount or repurchase price due. Under the terms
of the indenture for the notes, we may elect, if we meet certain conditions, to
pay the repurchase price with shares of common stock. Any future borrowing
arrangements or agreements relating to senior debt to which we become a party
may contain restrictions on, or prohibitions against, our repayments or
repurchases of the notes. If the maturity date or change in control occurs at a
time when our other arrangements prohibit us from repaying or repurchasing the
notes, we could try to obtain the consent of the lenders under those
arrangements, or we could attempt to refinance the borrowings that contain the
restrictions. If we do not obtain the necessary consents or refinance these
borrowings, we will be unable to repay or repurchase the notes. In that case,
our failure to repurchase any tendered notes or repay the notes due upon
maturity would constitute an event of default under the indenture. Any such
default, in turn, may cause a default under the terms of our senior debt. As a
result, in those circumstances, the subordination provisions of the indenture
would, absent a waiver, prohibit any repayment or repurchase of the notes until
we pay the senior debt in full.

There may be no public market for the notes.

     While the outstanding notes are eligible for trading in the Private
Offering, Resale, and Trading through Automated Linkages (PORTAL) Market of the
National Association of Securities Dealers, Inc., a screen-based automated
market for trading securities for qualified institutional buyers, there is no
public trading market for the notes. Although the initial purchasers of the
notes have advised us that they intend to make a market in the notes, they are
not obligated to do so and may discontinue their market-making activities at any
time without notice. Consequently, we do not know if any market for the notes
will develop, or if one does develop, that it will continue for any period of
time. If an active market for the notes fails to develop or continue, this
failure could harm the trading price and liquidity of the notes. We do not
intend to apply for listing of the notes on any securities exchange or any
automated quotation system.

AmerisourceBergen may not realize all of the anticipated benefits of the merger.

     The success of the merger will depend in part on our ability to realize the
anticipated synergies of $125 million per year by the end of the third year of
the existence of AmerisourceBergen and growth opportunities from integrating the
businesses of AmeriSource and Bergen. Our success in realizing these synergies,
cost savings and growth opportunities, and the timing of this realization,
depends on the successful integration of AmeriSource's and Bergen's operations.
Even if we are able to integrate the business operations of AmeriSource and
Bergen successfully, we cannot assure you that this integration will result in
the realization of the full benefits of the synergies, cost savings and growth
opportunities that we currently expect to result from this integration or that
these benefits will be achieved within the anticipated time frame. For example,
the elimination of duplicative costs may not be possible or may take longer than
anticipated and the benefits from the merger may be offset by costs incurred in
integrating the companies.

Intense competition may erode our profit margins.

     The wholesale distribution of pharmaceuticals and related healthcare
services is highly competitive. We compete primarily with the following:

     .    national wholesale distributors of pharmaceuticals such as Cardinal
          Health, Inc. and McKesson Corporation;

     .    regional and local distributors of pharmaceuticals;

     .    chain drugstores that warehouse their own pharmaceuticals;

                                       11


     .    manufacturers who distribute their products directly to customers; and

     .    other specialty distributors.

     Some of our competitors have greater financial resources than we have.
Competitive pressures have contributed to a decline in AmeriSource's and
Bergen's pharmaceutical wholesale drug distribution gross profit margins on
operating revenue from 5.2% in fiscal 1996 to 4.3% in fiscal 2000 on a combined
basis. This trend may continue and our business could be adversely affected as a
result.

     PharMerica faces competitive pressure from other market participants that
are significantly larger than it is and that have significantly greater
financial resources than it does. These competitive pressures could lead to a
decline in gross profit margins for PharMerica in the future. In addition, there
are relatively few barriers to entry in the local markets served by PharMerica,
and PharMerica may encounter substantial competition from new local market
entrants. These factors could adversely affect PharMerica's business in the
future.

The changing United States healthcare environment may impact our revenue and
income.

     Our products and services are intended to function within the structure of
the healthcare financing and reimbursement system currently existing in the
United States. In recent years, the healthcare industry has undergone
significant changes in an effort to reduce costs and government spending. These
changes include an increased reliance on managed care, cuts in Medicare funding
affecting our healthcare provider customer base, consolidation of competitors,
suppliers and customers, and the development of large, sophisticated purchasing
groups. We expect the healthcare industry to continue to change significantly in
the future. Some of these potential changes, such as a reduction in governmental
support of healthcare services or adverse changes in legislation or regulations
governing prescription drug pricing, healthcare services or mandated benefits,
may cause healthcare industry participants to greatly reduce the amount of our
products and services they purchase or the price they are willing to pay for our
products and services. Changes in pharmaceutical manufacturers' pricing or
distribution policies could also significantly reduce our income.

Our operating revenue and profitability may suffer upon our loss of, or the
bankruptcy or insolvency of, a significant customer.

     During the fiscal year ended September 30, 2000 and the six-month period
ended March 31, 2001, sales to the Veterans Administration accounted for 7.3%
and 7.6%, respectively, of our pro forma operating revenue. In addition, we
have contracts with group purchasing organizations ("GPOs") which represent a
concentration of buying power among multiple healthcare providers. While we
believe the risk of default by a federal government agency is minimal and the
credit risk with a GPO contract is spread among the members of the GPO that
purchase products from the Company, loss of a major federal government customer
or GPO could lead to a significant reduction in revenue. We otherwise have no
individual customer that accounted for more than 4.3% of our pro forma fiscal
2000 operating revenue.

Failure in our information technology systems could significantly disrupt our
operations, which could reduce our customer base and result in lost revenue.

     Our success depends, in part, on the continued and uninterrupted
performance of our information technology, or IT, systems. Our computer systems
are vulnerable to damage from a variety of sources, including telecommunications
failures, malicious human acts and natural disasters. Moreover, despite network
security measures, some of our servers are potentially vulnerable to physical or
electronic break-ins, computer viruses and similar disruptive problems. Despite
the precautions we have taken, unanticipated problems affecting our systems
could cause failures in our IT systems. Sustained or repeated system failures
that interrupt our ability to process test orders, deliver test results or
perform tests in a timely manner would adversely affect our reputation and
result in a loss of customers and net revenue.

     In addition, the wholesale drug distribution businesses of AmeriSource and
Bergen were based on different IT systems. We are in the process of evaluating
the differing systems and intend to use a common IT system in the future. This
process is complex and will take several years to complete. During systems
conversions of this type, workflow may be temporarily interrupted, which may
cause interruptions in customer service. In addition, the implementation
process, including the transfer of databases and master files to new data
centers, presents significant conversion risks which could cause failures in our
IT systems and disrupt our operations.

                                       12


Our operations may suffer if government regulations regarding pharmaceuticals
change.

     The healthcare industry is highly regulated at the local, state and federal
level. Consequently, we are subject to the risk of changes in various local,
state, federal and international laws, which include the operating and security
standards of the United States Drug Enforcement Administration, or DEA, the Food
and Drug Administration, or FDA, various state boards of pharmacy and comparable
agencies. These changes may affect our operations, including distribution of
prescription pharmaceuticals (including certain controlled substances),
operation of pharmacies and packaging of pharmaceuticals. A review of our
business by regulatory authorities may result in determinations that could
adversely affect the operations of the business.

If we fail to comply with extensive laws and regulations in respect of
healthcare fraud, we could suffer penalties or be required to make significant
changes to our operations.

     We are subject to extensive and frequently changing local, state and
federal laws and regulations relating to healthcare fraud. The federal
government continues to strengthen its position and scrutiny over practices
involving healthcare fraud affecting the Medicare, Medicaid and other government
healthcare programs. Contractual relationships with pharmaceutical manufacturers
and healthcare providers subject our business to provisions of the federal
Social Security Act which, among other things, (i) preclude persons from
soliciting, offering, receiving or paying any remuneration in order to induce
the referral of a patient for treatment or for inducing the ordering or
purchasing of items or services that are in any way paid for by Medicare,
Medicaid or other government-sponsored healthcare programs and (ii) impose a
number of restrictions upon referring physicians and providers of designated
health services under Medicare and Medicaid programs. Legislative provisions
relating to healthcare fraud and abuse give federal enforcement personnel
substantially increased funding, powers and remedies to pursue suspected fraud
and abuse. While we believe that we are in material compliance with all
applicable laws, many of the regulations applicable to us, including those
relating to marketing incentives offered by pharmaceutical suppliers, are vague
or indefinite and have not been interpreted by the courts. They may be
interpreted or applied by a prosecutorial, regulatory or judicial authority in a
manner that could require us to make changes in our operations. If we fail to
comply with applicable laws and regulations, we could suffer civil and criminal
penalties, including the loss of licenses or our ability to participate in
Medicare, Medicaid and other federal and state healthcare programs.

If key managers leave the Company, our operating results may be adversely
affected.

     We depend on our senior management. If some of these employees leave us,
operating results could be adversely affected. We cannot be assured that we will
be able to retain these or any other key employees.

Federal and state laws that protect patient health information may increase our
costs and limit our ability to collect and use that information.

     Our activities subject us to numerous federal and state laws and
regulations governing the collection, dissemination, use, security and
confidentiality of patient-identifiable health information, including the
federal Health Insurance Portability and Accountability Act of 1996, or HIPAA,
and related rules and regulations, or Privacy Laws. For example, as part of
PharMerica's pharmaceutical dispensing, medical record keeping, third party
billing and other services, we collect and maintain patient-identifiable health
information, which activities may trigger certain requirements under the Privacy
Laws. The costs associated with our efforts to comply with the Privacy Laws
could be substantial. Moreover, if we fail to comply with certain Privacy Laws,
we could suffer civil and criminal penalties. We can provide no assurance that
the costs incurred in complying or penalties we may incur for failure to comply
with the Privacy Laws will not have a material effect on us.

Our growth may be limited if we are not able to implement our acquisition
strategy.

     Since 1995, and prior to the merger of AmeriSource and Bergen, each of
AmeriSource and Bergen completed several acquisitions. Through these
acquisitions and other investments, AmeriSource and Bergen expanded their
respective geographic presence and breadth of service offerings. We expect to
continue to acquire companies as an element of our growth strategy. We may not
however be able to identify suitable acquisition candidates or to complete
acquisitions on favorable terms. We also may not be able to successfully
integrate acquired businesses in a timely or efficient manner.

                                       13


                                USE OF PROCEEDS

     We will not receive any proceeds from the sale by any selling
securityholder of the notes or the underlying common stock.

                                       14


                      RATIO OF EARNINGS TO FIXED CHARGES

                               AmerisourceBergen

     The following table summarizes the ratios of earnings to fixed charges for
AmerisourceBergen which were calculated using summary unaudited pro forma
consolidated statement of operations data for the year ended September 30, 2000,
and the six months ended March 31, 2001. The summary unaudited pro forma
consolidated statement of operations data used in the calculations were prepared
under the purchase method of accounting as if the merger between AmeriSource and
Bergen and the related financing transactions had been completed on October 1,
1999. We have included this information only for purposes of illustration, and
it does not necessarily indicate what the ratios of earnings to fixed charges
would have been if the merger and the related financing transactions had not
been completed on October 1, 1999. Moreover, this information does not
necessarily indicate what the future ratios of earnings to fixed charges will
be. You should read this table in conjunction with the "AmerisourceBergen
Corporation Unaudited Pro Forma Consolidated Condensed Financial Information"
included in the Current Report on Form 8-K filed by AmerisourceBergen on August
1, 2001, which is incorporated herein by reference.





                                                                      YEAR ENDED         SIX MONTHS ENDED
                                                                  SEPTEMBER 30, 2000       MARCH 31, 2001
                                                                ----------------------  --------------------
                                                                                  
Ratio of earnings to fixed charges...........................            2.1                     2.6




     The above ratios of earnings to fixed charges have been computed by
dividing our earnings from continuing operations before income taxes,
distribution on preferred securities of subsidiary trust and fixed charges, by
the fixed charges. For purposes of these ratios, fixed charges consist of
interest, whether expensed or capitalized, amortization of deferred financing
costs, distributions on preferred trust securities and the portion of rent
expense representative of interest. The ratios are derived from pro forma
financial information that gives effect to the issuance of $500 million Senior
Notes due 2008.

     (1)  The pro forma ratio of earnings to fixed charges for the nine months
ended June 30, 2001 will be included in a Current Report on Form 8-K to be filed
by AmerisourceBergen pursuant to the requirements of Item 2 of Form 8-K and,
upon filing of such Form 8-K, will be incorporated herein by reference.

                                  AmeriSource



                                   Period From       Fiscal        Fiscal        Fiscal        Fiscal        Fiscal
                                    October 1,     Year Ended    Year Ended    Year Ended    Year Ended    Year Ended
                                   2000 to June     September     September     September     September     September
                                     30, 2001       30, 2000      30, 1999      30, 1998      30, 1997      30, 1996
                                   ------------   ------------  ------------  ------------  ------------  ------------
                                                                                        
Ratio of earnings to fixed
charges.......................             5.2           4.3            3.6           2.3           2.7           2.6



     The above ratios of earnings to fixed charges have been computed by
dividing AmeriSource's earnings from continuing operations before income taxes,
extraordinary loss and fixed charges, by the fixed charges. For purposes of
these ratios, fixed charges consist of interest expense and the portion of rent
expense representative of interest.


                           DESCRIPTION OF THE NOTES

     AmeriSource issued the notes and AmeriSource Corporation issued the
subsidiary guarantee under a document called the "Indenture." On August __,
2001, AmerisourceBergen, AmeriSource, AmeriSource Corporation and Bank One Trust
Company, N.A., as Trustee (the "Trustee") executed a First Supplemental
Indenture to have AmerisourceBergen become a co-obligor of the notes and to
provide for the conversion of the notes into AmerisourceBergen common stock. The
Indenture and the First Supplemental Indenture are collectively referred to in
this "Description of the Notes" as the Indenture. The Indenture, the notes and
the subsidiary guarantee are governed by New York law. Because this section is a
summary, it does not describe every aspect of the notes, the subsidiary
guarantee and the Indenture. This summary is subject to and qualified in its
entirety by reference to all of the provisions of the Indenture, including
definitions of certain terms used in the Indenture. For example, in this section
we use capitalized words to signify defined terms that have been given special
meaning in the Indenture. We describe the meaning of only the more important
terms. Wherever we refer to particular defined terms, those defined terms are
incorporated by reference here. In this section, references to AmerisourceBergen
refer to AmerisourceBergen and not its subsidiaries, references to AmeriSource
refer to AmeriSource and not its subsidiaries and references to "we," "our" or
"us" refer to AmerisourceBergen and AmeriSource (or, as the context requires,
either AmerisourceBergen or AmeriSource) and not their respective subsidiaries.

                                       15


General

     The notes are general, unsecured obligations of AmerisourceBergen and
AmeriSource. The notes are subordinated, which means that they rank behind
certain of indebtedness as described below. The notes are limited to
$300,000,000 aggregate principal amount. We are required to repay the principal
amount of the notes in full on December 1, 2007. The notes bear interest at the
rate of 5% per annum. We will pay interest on the notes on June 1 and December 1
of each year, commencing on June 1, 2001.

     A holder of notes may convert the notes into shares of AmerisourceBergen
common stock initially at the conversion rate of 18.8791 shares per $1,000 in
principal amount of notes at any time before the close of business on December
1, 2007, unless the notes have been previously redeemed or repurchased. The
conversion rate may be adjusted as described below.

     AmeriSource may redeem the notes at our option at any time on or after
December 3, 2004, in whole or in part, at the redemption prices set forth below
under "--Optional Redemption," plus accrued and unpaid interest to the
redemption date. If there is a Change in Control of AmerisourceBergen, you may
have the right to require us to repurchase your notes as described below
under "-- Repurchase at Option of Holders Upon a Change in Control."

Form, Denomination, Transfer, Exchange And Book-Entry Procedures

     The notes were issued:

     .    only in fully registered form;

     .    without interest coupons; and

     .    in denominations of $1,000 and greater multiples.

     The notes that are sold under this prospectus will be evidenced by one or
more global notes which are deposited with the Trustee as custodian for DTC and
registered in the name of Cede & Co. ("Cede"), as nominee of DTC. Except as set
forth below, record ownership of the global note may be transferred, in whole or
in part, only to another nominee of DTC or to a successor of DTC or its nominee.

     The global note will not be registered in the name of any person, or
exchanged for notes that are registered in the name of any person, other than
DTC or its nominee unless either of the following occurs:

     .    DTC notifies us that it is unwilling, unable or no longer qualified to
          continue acting as the depositary for the global note; or

     .    an event of default with respect to the notes represented by the
          global note has occurred and is continuing.

          In those circumstances, DTC will determine in whose names any
securities issued in exchange for the global note will be registered.

          DTC or its nominee will be considered the sole owner and holder of the
global note for all purposes, and as a result:

     .    you cannot get notes registered in your name if they are represented
          by the global note;

     .    you cannot receive certificated (physical) notes in exchange for your
          beneficial interest in the global notes;

     .    you will not be considered to be the owner or holder of the global
          note or any note it represents for any purpose; and

     .    all payments on the global note will be made to DTC or its nominee.

                                       16


     The laws of some jurisdictions require that certain kinds of purchasers
(for example, certain insurance companies) can only own securities in definitive
(certificated) form. These laws may limit your ability to transfer your
beneficial interests in the global note to these types of purchasers.

     Only institutions (such as a securities broker or dealer) that have
accounts with the DTC or its nominee (called "participants") and persons that
may hold beneficial interests through participants can own a beneficial interest
in the global note. The only place where the ownership of beneficial interests
in the global note will appear and the only way the transfer of those interests
can be made will be on the records kept by DTC (for their participants'
interests) and the records kept by those participants (for interests of persons
held by participants on their behalf).

     Secondary trading in bonds and notes of corporate issuers is generally
settled in clearinghouse (that is, next-day) funds. In contrast, beneficial
interests in a global note usually trade in DTC's same-day funds settlement
system, and settle in immediately available funds. We make no representations as
to the effect that settlement in immediately available funds will have on
trading activity in those beneficial interests.

     We will make cash payments of interest on and principal of and the
redemption or repurchase price of the global note, as well as any payment of
Liquidated Damages, to Cede, the nominee for DTC, as the registered owner of the
global note. We will make these payments by wire transfer of immediately
available funds on each payment date.

     We have been informed that DTC's practice is to credit participants'
accounts on the payment date with payments in amounts proportionate to their
respective beneficial interests in the notes represented by the global note as
shown on DTC's records, unless DTC has reason to believe that it will not
receive payment on that payment date. Payments by participants to owners of
beneficial interests in notes represented by the global note held through
participants will be the responsibility of those participants, as is now the
case with securities held for the accounts of customers registered in "street
name".

     We will send any redemption notices to Cede. We understand that if less
than all the notes are being redeemed, DTC's practice is to determine by lot the
amount of the holdings of each participant to be redeemed.

     We also understand that neither DTC nor Cede will consent or vote with
respect to the notes. We have been advised that under its usual procedures, DTC
will mail an "omnibus proxy" to us as soon as possible after the record date.
The omnibus proxy assigns Cede's consenting or voting rights to those
participants to whose accounts the notes are credited on the record date
identified in a listing attached to the omnibus proxy.

     Because DTC can only act on behalf of participants, who in turn act on
behalf of indirect participants, the ability of a person having a beneficial
interest in the principal amount represented by the global note to pledge the
interest to persons or entities that do not participate in the DTC book-entry
system, or otherwise take actions in respect of that interest, may be affected
by the lack of a physical certificate evidencing its interest.

     DTC has advised us that it will take any action permitted to be taken by a
holder of notes (including the presentation of notes for exchange) only at the
direction of one or more participants to whose account with DTC interests in the
global note are credited and only in respect of such portion of the principal
amount of the notes represented by the global note as to which such participant
or participants has or have given such direction.

     DTC has also advised us as follows: DTC is a limited purpose trust company
organized under the laws of the State of New York, a member of the Federal
Reserve System, a "clearing corporation" within the meaning of the Uniform
Commercial Code, as amended, and a "clearing agency" registered pursuant to the
provisions of Section 17A of the Securities and Exchange Act of 1934, as amended
(the "Exchange Act"). DTC was created to hold securities for its participants
and facilitate the clearance and settlement of securities transactions between
participants through electronic book-entry changes in accounts of its
participants. Participants include securities brokers and dealers, banks, trust
companies and clearing corporations and may include certain other organizations.
Certain of such participants (or their representatives), together with other
entities, own DTC. Indirect access to the DTC system is available to other
entities such as banks, brokers, dealers and trust companies that clear through
or maintain a custodial relationship with a participant, either directly or
indirectly.

                                       17


     The policies and procedures of DTC, which may change periodically, will
apply to payments, transfers, exchanges and other matters relating to beneficial
interests in the global note. We and the Trustee have no responsibility or
liability for any aspect of DTC's or any participants' records relating to
beneficial interests in the global note, including for payments made on the
global note, and we and the Trustee are not responsible for maintaining,
supervising or reviewing any of those records.

Conversion Rights

     A holder of notes may, at its option, convert any portion of the principal
amount of any note that is an integral multiple of $1,000 into shares of
AmerisourceBergen common stock at any time on or prior to the close of business
on the maturity date, unless the notes have been previously redeemed or
repurchased, at a conversion rate of 18.8791 shares of common stock per $1,000
principal amount of notes. The conversion rate is equivalent to a conversion
price of approximately $52.97 per share. The right of a holder of notes to
convert a note called for redemption or delivered for repurchase will terminate
at the close of business on the redemption date or repurchase date for that
note, unless we default in making the payment due upon redemption or repurchase.

     A holder of notes may convert all or part of any note by delivering the
note at the Corporate Trust Office of the Trustee in the Borough of Manhattan,
The City of New York, accompanied by a duly signed and completed notice of
conversion, a copy of which may be obtained by the Trustee. The conversion date
will be the date on which the note and the duly signed and completed notice of
conversion are so delivered.

     As promptly as practicable on or after the conversion date,
AmerisourceBergen will issue and deliver to the Trustee a certificate or
certificates for the number of full shares of AmerisourceBergen common stock
issuable upon conversion, together with payment in lieu of any fraction of a
share. The certificate will then be sent by the Trustee to the conversion agent
for delivery to the holder. The shares of AmerisourceBergen common stock
issuable upon conversion of the notes will be fully-paid and nonassessable and
will rank equally with the other shares of AmerisourceBergen common stock.

     If a holder of notes surrenders a note for conversion on a date that is not
an Interest Payment Date, the holder will not be entitled to receive any
interest for the period from the next preceding Interest Payment Date to the
conversion date, except as described below in this paragraph. Any note
surrendered for conversion during the period from the close of business on any
Regular Record Date to the opening of business on the next succeeding Interest
Payment Date (except notes (or portions thereof) called for redemption on a
redemption date or to be repurchased on a repurchase date for which the right to
convert would terminate during such period) must be accompanied by payment of an
amount equal to the interest payable on such Interest Payment Date on the
principal amount of notes being surrendered for conversion. In the case of any
note which has been converted after any Regular Record Date but before the next
succeeding Interest Payment Date, interest payable on such Interest Payment Date
shall be payable on such Interest Payment Date notwithstanding such conversion,
and such interest shall be paid to the holder of such note on such Regular
Record Date.

     No other payment or adjustment for interest, or for any dividends in
respect of AmerisourceBergen common stock, will be made upon conversion. Holders
of our common stock issued upon conversion will not be entitled to receive any
dividends payable to holders of common stock as of any record time or date
before the close of business on the conversion date. We will not issue
fractional shares upon conversion. Instead, AmerisourceBergen will pay cash
based on the market price of AmerisourceBergen common stock at the close of
business on the conversion date.

     A holder of notes will not be required to pay any stamp or similar taxes or
duties relating to the issue or delivery of AmerisourceBergen common stock on
conversion but will be required to pay any stamp or similar tax or duty relating
to any transfer involved in the issue or delivery of AmerisourceBergen common
stock in a name other than that of the holder. Certificates representing shares
of AmerisourceBergen common stock will not be issued or delivered unless all
stamp or similar taxes and duties, if any, payable by the holder have been paid.
The conversion of notes into AmerisourceBergen common stock may be considered a
taxable exchange for federal income tax purposes. See "Certain United States
Federal Income and Estate Tax Consequences -- Tax Consequences to U.S. Holders."

     The conversion rate will be subject to adjustment for, among other
things:

     .    dividends (and other distributions) payable in AmerisourceBergen
          common stock on shares of AmerisourceBergen capital stock,

     .    the issuance to all holders of AmerisourceBergen common stock of
          rights, options or warrants entitling them to subscribe for or
          purchase AmerisourceBergen common stock at less than the then Current
          Market Price of such common stock

                                       18


         (determined as provided in the Indenture) as of the record date for
         stockholders entitled to receive such rights, options or warrants,

     .   subdivisions, combinations and reclassifications of AmerisourceBergen
         common stock,

     .   distributions to all holders of AmerisourceBergen common stock of
         evidences of indebtedness of AmerisourceBergen, shares of capital
         stock, cash or assets (including securities, but excluding those
         dividends, rights, options, warrants and distributions referred to
         above, dividends and distributions paid exclusively in cash and
         distributions upon mergers or consolidations discussed below),

     .   distributions consisting exclusively of cash (excluding any cash
         portion of distributions referred to in the immediately preceding
         clause, or cash distributed upon a merger or consolidation to which the
         next succeeding paragraph applies) to all holders of AmerisourceBergen
         common stock in an aggregate amount that, combined together with (1)
         other such all-cash distributions made within the preceding 365-day
         period in respect of which no adjustment has been made and (2) any cash
         and the fair market value of other consideration payable in connection
         with any tender offer by AmerisourceBergen or any of its subsidiaries
         for AmerisourceBergen common stock concluded within the preceding 365-
         day period in respect of which no adjustment has been made, exceeds 10%
         of AmerisourceBergen's market capitalization (being the product of the
         Current Market Price per share of the common stock on the record date
         for such distribution and the number of shares of common stock then
         outstanding), and

       . the successful completion of a tender offer made by AmerisourceBergen
         or any of its subsidiaries for AmerisourceBergen common stock which
         involves an aggregate consideration that, together with (1) any cash
         and other consideration payable in a tender offer by us or any of our
         subsidiaries for AmerisourceBergen common stock expiring within the
         365-day period preceding the expiration of such tender offer in respect
         of which no adjustment has been made and (2) the aggregate amount of
         any such all-cash distributions referred to in the immediately
         preceding clause above to all holders of AmerisourceBergen common stock
         within the 365-day period preceding the expiration of such tender offer
         in respect of which no adjustments have been made, exceeds 10% of
         AmerisourceBergen's market capitalization on the expiration of such
         tender offer.

     AmerisourceBergen reserves the right to effect such increases in the
conversion rate in addition to those required by the foregoing provisions as
AmerisourceBergen considers to be advisable in order that any event treated for
United States federal income tax purposes as a dividend of stock or stock rights
will not be taxable to the recipients. AmerisourceBergen will not be required to
make any adjustment to the conversion rate until the cumulative adjustments
amount to 1.0% or more of the conversion rate. AmerisourceBergen will compute
all adjustments to the conversion rate and will give notice by mail to holders
of the registered notes of any adjustments.

     In case of any consolidation or merger of AmerisourceBergen with or into
another entity or any merger of another entity into AmerisourceBergen (other
than a merger which does not result in any reclassification, conversion,
exchange or cancellation of our common stock), or in case of any sale or
transfer of all or substantially all of AmerisourceBergen's assets, each note
then outstanding will become convertible only into the kind and amount of
securities, cash and other property receivable upon such consolidation, merger,
sale or transfer by a holder of the number of shares of common stock into which
the notes were convertible immediately prior to the consolidation or merger or
sale or transfer.

     AmerisourceBergen may increase the conversion rate for any period of at
least 20 days, upon at least 15 days notice, if the AmerisourceBergen Board of
Directors determines that the increase would be the in AmerisourceBergen's best
interest. The Board of Directors' determination in this regard will be
conclusive. AmerisourceBergen will give holders of notes at least 15 days'
notice of such an increase in the conversion rate. Any increase, however, will
not be taken into account for purposes of determining whether the closing price
of AmerisourceBergen common stock exceeds the conversion price by 105% in
connection with an event which otherwise would be a Change in Control as defined
below.

     If at any time AmerisourceBergen makes a distribution of property to
AmerisourceBergen's stockholders that would be taxable to such stockholders as a
dividend for United States federal income tax purposes, such as distributions of
evidences of indebtedness or assets of AmerisourceBergen, but generally not
stock dividends on common stock or rights to subscribe for common stock, and,
pursuant to the anti-dilution provisions of the Indenture, the number of shares
into which notes are convertible is increased, that increase may be deemed for
United States federal income tax purposes to be the payment of a taxable
dividend to holders of notes. See "Certain United States Federal Income and
Estate Tax Consequences--Tax Consequences to U.S. Holders."

                                      19


Subsidiary Guarantee

     AmeriSource Corporation, which is a direct subsidiary of AmeriSource and
an indirect subsidiary of AmerisourceBergen, has fully and unconditionally
guaranteed, on a subordinated basis, our obligations under the notes. The
obligations of AmeriSource Corporation under the subsidiary guarantee is
subordinated to the prior payment in full in cash or cash equivalents of all
Senior Debt of AmeriSource Corporation. The subordination provisions applicable
to the subsidiary guarantee are substantially the same as the subordination
provisions applicable to the notes. The obligations of AmeriSource Corporation
under the subsidiary guarantee are limited as necessary to seek to prevent such
subsidiary guarantee from constituting a fraudulent conveyance under applicable
law.

     AmeriSource Corporation may not sell or otherwise dispose of all or
substantially all of its assets, or consolidate with or merge with or into,
another person unless:

     .    immediately after giving effect to that transaction, no default or
          event of default exists under the Indenture; and

     .    the person acquiring the property in any similar sale or disposition
          or the person formed by or surviving any similar consolidation or
          merger assumes all the obligations of AmeriSource Corporation pursuant
          to a supplemental indenture satisfactory to the trustee.

     AmeriSource Corporation will be released from its subsidiary guarantee:

     .    in connection with any sale or other disposition of all or
          substantially all of its assets, if the disposition is to us; or

     .    in connection with any sale of all of its capital stock, if the person
          acquiring the capital stock assumes all the obligations of AmeriSource
          Corporation pursuant to a supplemental indenture satisfactory to the
          trustee.

Subordination

     The notes are subordinated and, as a result, the payment of the principal,
any premium and interest (including Liquidated Damages) on the notes, including
amounts payable on any redemption or repurchase, will be subordinated to the
prior payment in full, in cash or other payment satisfactory to holders of
Senior Debt, of all of our senior debt. The obligations of AmeriSource
Corporation under the subsidiary guarantee is subordinated to all existing and
future senior debt of AmeriSource Corporation.

     "Senior Debt" is defined in the Indenture with respect to each of
AmerisourceBergen, AmeriSource and AmeriSource Corporation to mean: the
principal of (and premium, if any) and interest (including all interest accruing
subsequent to the commencement of any bankruptcy or similar proceeding, whether
or not a claim for post-petition interest is allowable as a claim in any such
proceeding) on, and all fees and other amounts payable in connection with, the
following, whether absolute or contingent, secured or unsecured, due or to
become due, outstanding on the date of the Indenture or thereafter created,
incurred or assumed:


     .    indebtedness evidenced by a credit or loan agreement, note, bond,
          debenture or other written obligation,

     .    obligations for money borrowed and obligations under the receivables
          securitization facility,

     .    obligations evidenced by a note or similar instrument given in
          connection with the acquisition of any businesses, properties or
          assets of any kind,

     .    obligations (1) as lessee under leases required to be capitalized on
          the balance sheet of the lessee under generally accepted accounting
          principles or (2) as lessee under other leases for facilities, capital
          equipment or related assets, whether or not capitalized, entered into
          or leased for financing purposes,

     .    obligations under interest rate and currency swaps, caps, floors,
          collars, hedge agreements, forward contracts or similar agreements or
          arrangements,

                                       20


     .    obligations with respect to letters of credit, bankers' acceptances
          and similar facilities (including reimbursement obligations with
          respect to the foregoing),

     .    obligations issued or assumed as the deferred purchase price of
          property or services (but excluding trade accounts payable and accrued
          liabilities arising in the ordinary course of business),

     .    obligations of the type referred to in the above clauses of another
          person and all dividends of another person, the payment of which, in
          either case, we have assumed or guaranteed, or for which we are
          responsible or liable, directly or indirectly, jointly or severally,
          as obligor, guarantor or otherwise, or which are secured by a lien on
          our property, and

     .    renewals, extensions, modifications, replacements, restatements and
          refundings of, or any indebtedness or obligation issued in exchange
          for, any such indebtedness or obligation described in the above
          clauses of this definition.

Senior Debt will not include the notes or any other indebtedness or obligation
if its terms or the terms of the instrument under which or pursuant to which it
is issued expressly provide that it is not superior in right of payment to the
notes or the obligations under the subsidiary guarantee.

     AmerisourceBergen or AmeriSource may not make any payment on account of
principal, premium or interest (including Liquidated Damages, if any) on the
notes, or redemption or repurchase of the notes, if either of the following
occurs:

     .    AmerisourceBergen or AmeriSource, as the case may be, defaults in its
          obligations to pay principal, premium, interest or other amounts on
          its Senior Debt, including a default under any redemption or
          repurchase obligation, and the default continues beyond any grace
          period that AmerisourceBergen or AmeriSource may have to make those
          payments; or

     .    any other default occurs and is continuing on any Designated Senior
          Debt of AmerisourceBergen or AmeriSource, as the case may be, and (1)
          the default permits the holders of the Designated Senior Debt to
          accelerate its maturity and (2) the Trustee has received a notice (a
          "Payment Blockage Notice") of the default from AmerisourceBergen or
          AmeriSource, the holder of such debt or such other person permitted to
          give such notice under the Indenture.

     If payments of the notes have been blocked by a payment default on Senior
Debt, payments on the notes may resume when the payment default has been cured
or waived or ceases to exist. If payments on the notes have been blocked by a
nonpayment default, payments on the notes may resume on the earlier of (1) the
date the nonpayment default is cured or waived or ceases to exist or (2) 179
days after the Payment Blockage Notice is received.

     No nonpayment default that existed on the day a Payment Blockage Notice was
delivered to the Trustee can be used as the basis for any subsequent Payment
Blockage Notice. In addition, once a holder of Designated Senior Debt has
blocked payment on the notes by giving a Payment Blockage Notice, no new period
of payment blockage can be commenced pursuant to a subsequent Payment Blockage
Notice until both of the following are satisfied:

     .    365 days have elapsed since the effectiveness of the immediately prior
          Payment Blockage Notice; and

     .    all scheduled payments of principal, any premium and interest with
          respect to the notes that have come due have been paid in full in
          cash.

"Designated Senior Debt" means our obligations under the Liquidity Credit
Facility, the Receivables Securitization Facility and the Revolving Credit
Facility and under any other particular Senior Debt in which the instrument
creating or evidencing the same or the assumption or guarantee thereof (or
related agreements or documents to which we are a party), whether or not
executed contemporaneously with the issuance of such Senior Debt expressly
provides that such Senior Debt shall be "Designated Senior Debt" for purposes of
this prospectus (provided that such instrument, agreement or other document may
place limitations and conditions on the right of such Senior Debt to exercise
the rights of Designated Senior Debt).

"Liquidity Credit Facility" means the credit facility created pursuant to the
Liquidity Facility Credit Agreement dated as of October 3, 2000 among
AmeriSource Corporation, as borrower, AmeriSource Health Corporation, as a
guarantor, the lenders identified therein and Bank of America, N.A. as
administrative agent, as such agreement has been or may be amended,
supplemented, restated, extended, renewed or otherwise modified from time to
time and includes any agreement

                                       21


(and all successor agreements thereto) extending the maturity of, refinancing or
otherwise restructuring all or any portion of the indebtedness under such
agreement or any successor agreement.

"Receivables Securitization Facility" means a credit facility which was entered
into pursuant to the Receivables Purchase Agreement, dated May 14, 1999, among
AmeriSource Receivables Financial Corporation, as seller, AmeriSource
Corporation, as servicer, AmeriSource Health Corporation, as guarantor, Delaware
Funding Corporation, as buyer, and Morgan Guaranty Trust Company of New York, as
administrative agent, as such agreement has been or may be amended,
supplemented, restated, extended, renewed or otherwise modified from time to
time and includes any agreement (and all successor agreements thereto) extending
the maturity of, refinancing or otherwise restructuring all or any portion of
the indebtedness under such agreement or any successor agreement.

"Revolving Credit Facility" means a credit facility created pursuant to the
Revolving Credit Agreement dated as of January 8, 1997 among AmeriSource
Corporation, as borrower, AmeriSource Health Corporation, as a guarantor, the
lenders identified therein and Bank of America, N.A., as administrative agent,
as such agreement has been or may be amended, supplemented, restated, extended,
renewed or otherwise modified from time to time and includes any agreement (and
all successor agreements thereto) extending the maturity of, refinancing or
otherwise restructuring all or any portion of the indebtedness under such
agreement or any successor agreement.

     In addition, upon any acceleration of the principal due on the notes as a
result of an Event of Default or payment or distribution of our assets to
creditors upon any dissolution, winding up, liquidation or reorganization,
whether voluntary or involuntary, marshaling of assets, assignment for the
benefit of creditors, or in bankruptcy, insolvency, receivership or other
similar proceedings, all principal, premium, if any, interest and other amounts
due on all of our Senior Debt must be paid in full before a holder of notes is
entitled to receive any payment. By reason of such subordination, in the event
of insolvency, our creditors who are holders of our Senior Debt are likely to
recover more, ratably, than a holder of notes is, and a holder of notes will
likely experience a reduction or elimination of payments on the notes.

     The Indenture does not limit our ability or the ability of AmeriSource
Corporation to incur Senior Debt or our ability or the ability of AmeriSource
Corporation or our other subsidiaries to incur any other indebtedness.

Optional Redemption

     On or after December 3, 2004, AmeriSource may redeem the notes, in whole or
in part, at the prices set forth below. If AmeriSource elects to redeem all or
part of the notes, AmeriSource will give at least 30, but no more than 60, days
notice to you.

     The redemption price, expressed as a percentage of principal amount, is as
follows for the 12-month periods beginning on December 1 of the following years
(December 3, 2004 through December 1, 2005 in the case of the first such
period):

                                                   Redemption
                        Year                         Price
                        ----                       ----------
                        2004                        102.143%
                        2005                        101.429%
                        2006                        100.714%


and thereafter is equal to 100% of the principal amount, in each case together
with accrued interest to the date of redemption.

     No sinking fund is provided for the notes, which means that the Indenture
does not require us to redeem or retire the notes periodically.

Payment and Conversion

     We will make all payments of principal and interest on the notes by dollar
check drawn on an account maintained at a bank in The City of New York. If a
holder of notes holds registered notes with a face value greater than
$2,000,000, at the request of the holder we will make payments of principal or
interest to the holder by wire transfer to an account

                                       22


maintained by the holder at a bank in The City of New York. Payment of any
interest on the notes will be made to the person in whose name the note, or any
predecessor note, is registered at the close of business on December 1 or June 1
(whether or not a business day) immediately preceding the relevant Interest
Payment Date (a "Regular Record Date"). If a holder of notes holds registered
notes with a face value in excess of $2,000,000 and the holder would like to
receive payments by wire transfer, the holder will be required to provide the
Trustee with wire transfer instructions at least 15 days prior to the relevant
payment date.

     Payments on any global note registered in the name of DTC or its nominee
will be payable by the Trustee to DTC or its nominee in its capacity as the
registered holder under the Indenture. Under the terms of the Indenture, we and
the Trustee will treat the persons in whose names the notes, including any
global note, are registered as the owners for the purpose of receiving payments
and for all other purposes. Consequently, neither we, the Trustee nor any of our
agents or the Trustee's agents has or will have any responsibility or liability
for (1) any aspect of DTC's records or any participant's or indirect
participant's records relating to or payments made on account of beneficial
ownership interests in the global note, or for maintaining, supervising or
reviewing any of DTC's records or any participant's or indirect participant's
records relating to the beneficial ownership interests in the global note, or
(2) any other matter relating to the actions and practices of DTC or any of its
participants or indirect participants.

     We will not be required to make any payment on the notes due on any day
which is not a business day until the next succeeding business day. The payment
made on the next succeeding business day will be treated as though it were paid
on the original due date and no interest will accrue on the payment for the
additional period of time.

     Notes may be surrendered for conversion at the Corporate Trust Office of
the Trustee in the Borough of Manhattan, The City of New York. Notes surrendered
for conversion must be accompanied by appropriate notices and any payments in
respect of interest or taxes, as applicable, as described above under "--
Conversion Rights."

     We have initially appointed the Trustee as paying agent and conversion
agent. We may terminate the appointment of any paying agent or conversion agent
and appoint additional or other paying agents and conversion agents. However,
until the notes have been delivered to the Trustee for cancellation, or moneys
sufficient to pay the principal of, premium, if any, and interest on the notes
have been made available for payment and either paid or returned to us as
provided in the Indenture, the Trustee will maintain an office or agency in the
Borough of Manhattan, The City of New York for surrender of notes for
conversion. Notice of any termination or appointment and of any change in the
office through which any paying agent or conversion agent will act will be given
in accordance with "--Notices" below.

     All moneys deposited with the Trustee or any paying agent, or then held by
us, in trust for the payment of principal of, premium, if any, or interest on
any notes which remain unclaimed at the end of two years after the payment has
become due and payable will be repaid to us, and a holder of notes will then
look only to us for payment.

                                       23


Repurchase at Option of Holders Upon a Change in Control

     If a Change in Control as defined below occurs, a holder of notes will have
the right, at its option, to require us to repurchase all of the notes not
previously called for redemption, or any portion of the principal amount
thereof, that is equal to $1,000 or an integral multiple of $1,000. The price we
are required to pay is 100% of the principal amount of the notes to be
repurchased, together with interest accrued to, but excluding, the repurchase
date.

     At AmerisourceBergen's option, instead of paying the repurchase price in
cash, AmerisourceBergen may pay the repurchase price in AmerisourceBergen common
stock valued at 95% of the average of the closing prices of our common stock for
the five trading days immediately preceding and including the third day prior to
the repurchase date. AmerisourceBergen may only pay the repurchase price in
AmerisourceBergen common stock if AmerisourceBergen satisfies conditions
provided in the Indenture.

     Within 30 days after the occurrence of a Change in Control, we are
obligated to give to the holders of notes notice of the Change in Control and of
the repurchase right arising as a result of the Change of Control. In addition,
at such time, AmerisourceBergen must give notice if AmerisourceBergen is
exercising its option to pay the repurchase price in AmerisourceBergen common
stock. We must also deliver a copy of this notice to the Trustee. To exercise
the repurchase right, a holder of notes must deliver on or before the 30th day
after the date of our notice irrevocable written notice to the Trustee of the
holder's exercise of its repurchase right, together with the notes with respect
to which the right is being exercised. We are required to repurchase the notes
on the date that is 45 days after the date of our notice.

     A Change in Control will be deemed to have occurred at the time after the
notes are originally issued that any of the following occurs:

          (1)  any person, including any syndicate or group deemed to be a
     "person" under Section 13(d)(3) of the Exchange Act, acquires beneficial
     ownership, directly or indirectly, through a purchase, merger or other
     acquisition transaction or series of transactions, of shares of
     AmerisourceBergen capital stock entitling the person to exercise 50% or
     more of the total voting power of all shares of AmerisourceBergen capital
     stock that is entitled to vote generally in elections of directors, other
     than an acquisition by AmerisourceBergen, any of its subsidiaries or any of
     its employee benefit plans; or

          (2)  AmerisourceBergen merges or consolidates with or into any other
     person, any merger of another person into AmerisourceBergen, or
     AmerisourceBergen conveys, sells, transfers or leases all or substantially
     all of its assets to another Person, other than any such transaction (a)
     that does not result in any reclassification, conversion, exchange or
     cancellation of outstanding shares of AmerisourceBergen capital stock, or
     (b) pursuant to which the holders of AmerisourceBergen common stock
     immediately prior to such transaction have the entitlement to exercise,
     directly or indirectly, 50% or more of the total voting power of all shares
     of capital stock entitled to vote generally in the election of directors of
     the continuing or surviving corporation immediately after such transaction,
     or (c) which is effected solely to change AmerisourceBergen's jurisdiction
     of incorporation and results in a reclassification, conversion or exchange
     of outstanding shares of AmerisourceBergen common stock into solely shares
     of common stock.

     However, a Change in Control will not be deemed to have occurred if either
(A) the closing price per share of AmerisourceBergen common stock for any five
trading days within the period of 10 consecutive trading days ending immediately
after the later of the Change in Control or the public announcement of the
Change in Control, in the case of a Change in Control relating to an acquisition
of capital stock, or the period of 10 consecutive trading days ending
immediately before the Change in Control, in the case of Change in Control
relating to a merger, consolidation or asset sale, equals or exceeds 105% of the
conversion price of the notes in effect on each of those trading days, or (B)
all of the consideration (excluding cash payments for fractional shares and cash
payments made pursuant to dissenters' appraisal rights) in a merger or
consolidation otherwise constituting a Change of Control under clause (1) and/or
clause (2) above consists of shares of common stock traded on a national
securities exchange or listed on the New York Stock Exchange (or will be so
traded or quoted immediately following such merger or consolidation) and as a
result of such merger or consolidation the notes become convertible into such
common stock.

     For purposes of these provisions:

     .    the conversion price is equal to $1,000 divided by the conversion
          rate;

                                       24


     .    whether a person is a "beneficial owner" will be determined in
          accordance with Rule 13d-3 under the Exchange Act; and

     .    "person" includes any syndicate or group that would be deemed to be a
          "person" under Section 13(d)(3) of the Exchange Act.

     Rule 13e-4 under the Exchange Act requires the dissemination of prescribed
information to securityholders in the event of an issuer tender offer and may
apply in the event that the repurchase option becomes available to the holders
of notes. We will comply with this rule to the extent it applies at that time.

     We may, to the extent permitted by applicable law, at any time purchase
notes in the open market, by tender at any price or by private agreement. Any
note that we purchase may, to the extent permitted by applicable law and subject
to restrictions contained in the purchase agreement with the Initial Purchasers,
be re-issued or resold or may, at our option, be surrendered to the Trustee for
cancellation. Any notes surrendered for cancellation may not be re-issued or
resold and will be canceled promptly.

     The definition of Change in Control includes a phrase relating to the
conveyance, transfer, sale, lease or disposition of "all or substantially all"
of AmerisourceBergen's assets. There is no precise, established definition of
the phrase "substantially all" under applicable law. Accordingly, the ability of
a holder of notes to require us to repurchase its notes as a result of
conveyance, transfer, sale, lease or other disposition of less than all of
AmerisourceBergen's assets may be uncertain.

     The foregoing provisions would not necessarily provide you with protection
if AmerisourceBergen is involved in a highly leveraged or other transaction that
may adversely affect the holders.

     Our ability to repurchase notes upon the occurrence of a Change in Control
is subject to important limitations. Some of the events constituting a Change in
Control could result in an event of default under our Senior Debt. Moreover, a
Change in Control could cause an event of default under, or be prohibited or
limited by, the terms of our Senior Debt. As a result, unless we were to obtain
a waiver, a repurchase of the notes in cash could be prohibited under the
subordination provisions of the Indenture until the Senior Debt is paid in full.
Although AmerisourceBergen has the right to repurchase the notes with
AmerisourceBergen common stock, subject to certain conditions, we cannot assure
you that we would have the financial resources, or would be able to arrange
financing, to pay the repurchase price in cash for all the notes that might be
delivered by holders of notes seeking to exercise the repurchase right. If we
were to fail to repurchase the notes when required following a Change in
Control, an Event of Default under the Indenture would occur, whether or not
such repurchase is permitted by the subordination provisions of the Indenture.
Any such default may, in turn, cause a default under our Senior Debt. See "--
Subordination".

Mergers and Sales of Assets

     We may not consolidate with or merge into any other person or convey,
transfer, sell or lease our properties and assets substantially as an entirety
to any person, and we may not permit any person to consolidate with or merge
into us or convey, transfer, sell or lease such person's properties and assets
substantially as an entirety to us unless:

     .    the person formed by such consolidation or into or with which we are
          merged or the person to which our properties and assets are so
          conveyed, transferred, sold or leased, shall be a corporation, limited
          liability company, partnership or trust organized and existing under
          the laws of the United States, any State within the United States or
          the District of Columbia and, if we are not the surviving person, the
          surviving person assumes the payment of the principal of, premium, if
          any, and interest on the notes and the performance of our other
          covenants under the Indenture, and

     .    immediately after giving effect to the transaction, no event of
          default, and no event that, after notice or lapse of time or both,
          would become an event of default, will have occurred and be
          continuing.

Events of Default

     The following will be Events of Default under the Indenture:

                                       25


     .    we fail to pay principal of or premium, if any, on any note when due,
          whether or not prohibited by the subordination provisions of the
          Indenture;

     .    we fail to pay any interest, including any Liquidated Damages, on any
          note when due, which failure continues for 30 days, whether or not
          prohibited by the subordination provisions of the Indenture;

     .    we fail to provide notice of a Change in Control, whether or not such
          notice is prohibited by the subordination provisions of the Indenture;

     .    we fail to perform any other covenant in the Indenture, which failure
          continues for 60 days after written notice as provided in the
          Indenture;

     .    any indebtedness under any bonds, debentures, notes or other evidences
          of indebtedness for money borrowed (or any guarantee thereof) by us or
          any of our significant subsidiaries in an aggregate principal amount
          in excess of $15.0 million is not paid when due either at its stated
          maturity or upon acceleration thereof, and such indebtedness is not
          discharged, or such acceleration is not rescinded or annulled, within
          a period of 30 days after notice as provided in the Indenture;

     .    certain events of bankruptcy, insolvency or reorganization involving
          us or any of our significant subsidiaries; or

     .    except as permitted by the Indenture, the subsidiary guarantee shall
          for any reason cease to be, or be asserted in writing by the
          AmeriSource Corporation or us not to be in full force and effect and
          enforceable in accordance with its terms.

     Subject to the provisions of the Indenture relating to the duties of the
Trustee in case an Event of Default shall occur and be continuing, the Trustee
will be under no obligation to exercise any of its rights or powers under the
Indenture at the request or direction of any holder, unless the holder shall
have offered reasonable indemnity to the Trustee. Subject to providing
indemnification of the Trustee, the holders of a majority in aggregate principal
amount of the outstanding notes will have the right to direct the time, method
and place of conducting any proceeding for any remedy available to the Trustee
or exercising any trust or power conferred on the Trustee.

     If an Event of Default, other than an Event of Default arising from events
of insolvency, bankruptcy or reorganization with respect to us or any of our
significant subsidiaries, occurs and is continuing, either the Trustee or the
holders of at least 25% in principal amount of the outstanding notes may,
subject to the subordination provisions of the Indenture, accelerate the
maturity of all notes. However, after such acceleration, but before a judgment
or decree based on acceleration, the holders of a majority in aggregate
principal amount of outstanding notes may, under certain circumstances, rescind
and annul the acceleration if all Events of Default, other than the non-payment
of principal of the notes which have become due solely by such declaration of
acceleration, have been cured or waived as provided in the Indenture. If an
Event of Default arising from events of insolvency, bankruptcy or reorganization
with respect to us occurs, then the principal of, and accrued interest on, all
the notes will automatically become immediately due and payable without any
declaration or other act on the part of the holders of the notes or the Trustee.
For information as to waiver of defaults, see "-- Meetings, Modification and
Waiver".

     A holder of notes will not have any right to institute any proceeding with
respect to the Indenture, or for any remedy under the Indenture, unless the
holder gives the Trustee written notice of a continuing Event of Default and the
holders of at least 25% in aggregate principal amount of the outstanding notes
have made written request, and offered reasonable indemnity, to the Trustee to
institute proceedings, and the Trustee has not received from the holders of a
majority in aggregate principal amount of the outstanding notes a direction
inconsistent with the written request and shall have failed to institute such
proceeding within 60 days. However, these limitations do not apply to a suit
instituted by a holder of notes for the enforcement of payment of the principal
of, premium, if any, or interest, including Liquidated Damages, on the holder's
note on or after the respective due dates expressed in its note or the holder's
right to convert its note in accordance with the Indenture.

     We will be required to furnish to the Trustee annually a statement as to
our performance of certain of our obligations under the Indenture and as to any
default in such performance.

                                       26


Meetings, Modification and Waiver

     The Indenture contains provision for convening meetings of the holders of
notes to consider matters affecting their interests.

     Certain limited modifications of the Indenture may be made without the
necessity of obtaining the consent of the holders of the notes. Other
modifications and amendments of the Indenture may be made, and certain past
defaults by us may be waived, either (i) with the written consent of the holders
of not less than a majority in aggregate principal amount of the notes at the
time outstanding or (ii) by the adoption of a resolution, at a meeting of
holders of the notes at which a quorum is present, by the holders of at least 66
2/3% in aggregate principal amount of the notes represented at such meeting. The
quorum at any meeting called to adopt a resolution will be persons holding or
representing a majority in aggregate principal amount of the notes at the time
outstanding and, at any reconvened meeting adjourned for lack of a quorum, 25%
of such aggregate principal amount.

     However, a modification or amendment requires the consent of the holder of
each outstanding note affected if it would:

     .    change the stated maturity of the principal or interest of a note;

     .    reduce the principal amount of, or any premium or interest on, any
          note;

     .    reduce the amount payable upon a redemption or mandatory repurchase;

     .    modify the provisions with respect to the repurchase rights of holders
          of notes in a manner adverse to the holders;

     .    change the place or currency of payment on a note;

     .    impair the right to institute suit for the enforcement of any payment
          on any note;

     .    modify our obligation to maintain an office or agency in New York
          City;

     .    modify the subordination provisions in a manner that is adverse to the
          holders of the notes;

     .    adversely affect the right to convert the notes;

     .    modify our obligation to deliver information required under Rule 144A
          to permit resales of the notes and common stock issued upon conversion
          of the notes if we cease to be subject to the reporting requirements
          under the Exchange Act;

     .    reduce the above-stated percentage of the principal amount of the
          holders whose consent is needed to modify or amend the Indenture;

     .    reduce the percentage of the principal amount of the holders whose
          consent is needed to waive compliance with certain provisions of the
          Indenture or to waive certain defaults; or

     .    reduce the percentage required for the adoption of a resolution or the
          quorum required at any meeting of holders of notes at which a
          resolution is adopted.

     The holders of a majority in aggregate principal amount of the outstanding
notes may waive compliance by us with certain restrictive provisions of the
Indenture by written consent. Holders of a majority of the principal amount of
notes attending a meeting may also waive compliance by us with certain
restrictive provisions of the Indenture by the adoption of a resolution at the
meeting if a quorum of holders are present and certain other conditions are met.
The holders of a majority in aggregate principal amount of the outstanding notes
also may waive by written consent any past default under the Indenture, except a
default in the payment of principal, premium, if any, or interest.

                                       27


Registration Rights

         The registration statement of which this prospectus forms a part has
been filed under the terms of a Registration Rights Agreement, which AmeriSource
entered into with the initial purchasers of the notes. In the Registration
Rights Agreement, AmeriSource and AmeriSource Corporation agree, for the benefit
of the holders of the notes and the shares of common stock issuable upon
conversion of the notes (together, the "Registrable Securities"), that
AmeriSource and AmeriSource Corporation would, at their expense:

     .    file with the SEC, within 90 days after the date the notes were
          originally issued, a shelf registration statement covering resales of
          the Registrable Securities, subject to the right to postpone the
          filing of the shelf registration statement for an additional 90 days
          in limited circumstances;

     .    use reasonable efforts to cause the shelf registration statement to be
          declared effective under the Securities Act within 180 days after the
          date the notes are originally issued, subject to the right to postpone
          having the shelf registration statement declared effective for an
          additional 90 days in limited circumstances; and

     .    use reasonable efforts to keep effective the shelf registration
          statement until two years after the date the notes are issued or, if
          earlier, until there are no outstanding Registrable Securities, which
          is referred to as the Effectiveness Period.

     AmeriSource will be permitted to suspend the use of this prospectus that is
part of the shelf registration statement in connection with the sales of
Registrable Securities during prescribed periods of time for reasons relating to
pending corporate developments, public filings with the SEC and other events.
The periods during which AmeriSource can suspend the use of the prospectus may
not, however, exceed a total of 45 days in any 90 day period or a total of 90
days in any 365-day period. Following the effectiveness of the registration
statement of which this prospectus forms a part, AmeriSource will provide to
each holder of Registrable Securities copies of this prospectus, notify each
holder that the shelf registration statement has become effective and take
certain other actions required to permit public resales of the Registrable
Securities.

     AmeriSource may, upon written notice to all the holders of notes, postpone
having the shelf registration statement declared effective for a reasonable
period not to exceed 90 days if AmeriSource possesses material nonpublic
information the disclosure of which would have a material adverse effect on
AmeriSource and its subsidiaries taken as a whole. Notwithstanding any such
postponement, additional interest, which is referred to as Liquidated Damages,
will accrue on the notes if either of the following events, which is referred to
as Registration Defaults occurs:

     .    on or prior to 90 days following the date the notes were originally
          issued, a shelf registration statement has not been filed with the
          SEC; or

     .    on or prior to 180 days following the date the notes were originally
          issued, the shelf registration statement is not declared effective.

     In that case, Liquidated Damages will accrue on the notes from and
including the day following the Registration Default to but excluding the day on
which the Registration Default has been cured. Liquidated Damages will be paid
semi-annually in arrears, with the first semi-annual payment due on the first
Interest Payment Date following the date on which the Liquidated Damages began
to accrue.

     The rates at which Liquidated Damages will accrue will be as follows:

     .    0.25% of the principal amount per annum to and including the 90th
          day after the Registration Default; and

     .    0.50% of the principal amount per annum from and after the 91st day
          after the Registration Default.

     In addition, the interest rate on the notes will be increased if:

     .    the shelf registration statement ceases to be effective, or
          AmeriSource otherwise prevents or restricts holders of Registrable
          Securities from making sales under the shelf registration statement,
          for more than 45 days, whether or not consecutive during any 90-day
          period; or

                                       28


     .    the shelf registration statement ceases to be effective, or
          AmeriSource otherwise prevent or restrict holders of Registrable
          Securities from making sales under the shelf registration statement,
          for more than 90 days, whether or not consecutive, during any 12-month
          period.

     In either event, the interest rate on the notes will increase by an
additional 0.50% per annum from the 46th day of the 90-day period or the 91st
day of the 12-month period. The increased rate will continue until the earlier
of the following:

     .    the time the shelf registration statement again becomes effective or
          the holders of Registrable Securities are again able to make sales
          under the shelf registration statement, depending on which event
          triggered the increase in interest rate; or

     .    the date the Effectiveness Period expires.

     A holder who elects to sell any Registrable Securities pursuant to the
shelf registration statement will be required to be named as a selling
securityholder in this prospectus, may be required to deliver a prospectus to
purchasers, may be subject to certain civil liability provisions under the
Securities Act in connection with those sales and is bound by the provisions of
the Registration Rights Agreement that apply to a holder making such an
election, including certain indemnification provisions.

     No holder of Registrable Securities will be entitled to be named as a
selling securityholder in this prospectus, and no holder of Registrable
Securities is entitled to use this prospectus for offers and resales of
Registrable Securities at any time, unless the holder has returned a completed
and signed Notice and Questionnaire to AmeriSource.

     Beneficial owners of Registrable Securities who have not returned a Notice
and Questionnaire to AmeriSource may receive another Notice and Questionnaire
from AmeriSource upon request. Following AmeriSource's receipt of a completed
and signed Notice and Questionnaire, AmeriSource will include the Registrable
Securities covered thereby in the shelf registration statement, subject to
restrictions on the timing and number of supplements to the shelf registration
statement provided in the Registration Rights Agreement.

     AmeriSource agreed in the Registration Rights Agreement to use its
reasonable efforts to cause the shares of common stock issuable upon conversion
of the notes to be listed on the New York Stock Exchange. However, if the
AmerisourceBergen common stock is not then listed on the New York Stock
Exchange, AmeriSource will use its reasonable efforts to cause the shares of
common stock issuable upon conversion of the notes to be quoted or listed on
whichever market or exchange the AmerisourceBergen common stock is then quoted
or listed, upon effectiveness of the shelf registration statement.

     This summary of certain provisions of the Registration Rights Agreement may
not contain all the information important to the holders of notes. Holders of
notes may request from AmerisourceBergen or AmeriSource a copy of the
Registration Rights Agreement.

Notices

     Notice to holders of the registered notes will be given by mail to the
addresses as they appear in the security register. Notices will be deemed to
have been given on the date of such mailing.

     Notice of a redemption of notes will be given not less than 30 nor more
than 60 days prior to the redemption date and will specify the redemption date.
A notice of redemption of the notes will be irrevocable.

Replacement of Notes

     We will replace any note that becomes mutilated, destroyed, stolen or lost
at the expense of the holder upon delivery to the Trustee of the mutilated notes
or evidence of the loss, theft or destruction satisfactory to us and the
Trustee. In the case of a lost, stolen or destroyed note, indemnity satisfactory
to the Trustee and us may be required at the expense of the holder of the note
before a replacement note will be issued.

Payment of Stamp and Other Taxes

     We have paid all stamp and other duties, if any, which may have been
imposed by the United States or any political subdivision thereof or taxing
authority thereof or therein with respect to the issuance of the notes. We were
not

                                       29


required to make any payment with respect to any other tax, assessment or
governmental charge imposed by any government or any political subdivision
thereof or taxing authority thereof or therein.

Governing Law

     The Indenture, the notes and the subsidiary guarantee are governed by and
construed in accordance with the laws of the State of New York, United States of
America.

The Trustee

     If an Event of Default occurs and is continuing, the Trustee will be
required to use the degree of care of a prudent person in the conduct of his own
affairs in the exercise of its powers. Subject to such provisions, the Trustee
will be under no obligation to exercise any of its rights or powers under the
Indenture at the request of any of the holders of notes, unless they shall have
offered to the Trustee reasonable security or indemnity.


       CERTAIN UNITED STATES FEDERAL INCOME AND ESTATE TAX CONSEQUENCES

     The following is a general discussion of certain U.S. federal income and
estate tax consequences to you of holding the notes and common stock issuable
upon conversion of the notes. This discussion is based upon the Internal Revenue
Code of 1986, as amended (the "Code"), U.S. Treasury Regulations
("Regulations"), Internal Revenue Service ("IRS") rulings and pronouncements,
and judicial decisions now in effect, all of which are subject to change
(possibly with retroactive effect) or different interpretation.

     This discussion is for your general information only and does not address
all aspects of U.S. federal income taxation that may be relevant to you. This
discussion does not describe the tax consequences arising under the laws of any
foreign, state or local jurisdiction, nor does it describe all of the tax
consequences to you in light of your personal circumstances (such as the U.S.
federal alternative minimum tax). It also does not address certain tax
consequences that may apply to you if you are subject to special tax rules, such
as if you are a financial institution, an insurance company, a tax-exempt
entity, a dealer in securities, if you hold the notes or common stock in
connection with a "straddle", "hedging", or "conversion" transaction for U.S.
federal income tax purposes, if you are a non-U.S. person, and your holding the
notes or common stock is effectively connected with a trade or business that you
conduct in the United States, or if your "functional currency" is not the U.S.
dollar. This discussion assumes that you acquired our notes on their original
issuance at their original offering price and hold the notes and common stock
received upon conversion thereof as capital assets within the meaning of Section
1221 of the Code. We have not sought any ruling from the IRS with respect to
statements made and the conclusions reached in this discussion and there can be
no assurance that the IRS will agree with our statements and conclusions.

     YOU ARE URGED TO CONSULT YOUR OWN TAX ADVISOR REGARDING THE FEDERAL, STATE,
LOCAL AND FOREIGN TAX CONSEQUENCES OF YOUR PARTICIPATION IN THIS OFFERING, AND
YOUR OWNERSHIP AND DISPOSITION OF THE NOTES (INCLUDING CONVERSION OF THE NOTES)
OR COMMON STOCK, INCLUDING THE EFFECT THAT YOUR PARTICULAR CIRCUMSTANCES MAY
HAVE ON THE TAX CONSEQUENCES OF YOUR PARTICIPATION IN THIS OFFERING, AS WELL AS
THE CONSEQUENCES OF ANY PROPOSED CHANGE IN THE APPLICABLE LAWS.

Tax Consequences to U.S. Holders

     The following tax discussion applies to you if you are a beneficial owner
of the notes or common stock and you are:

     .   a citizen or resident of the United States,

     .   a corporation (or other entity taxed as a corporation) created or
         organized under the laws of the United States or a political
         subdivision thereof,

     .   an estate the income of which is subject to U.S. federal income
         taxation regardless of source, or

                                       30


     .    a trust if (A) a U.S. court is able to exercise primary supervision
          over the trust's administration or (B) one or more U.S. persons, as
          defined under section 7701(a)(30) of the Code, have authority to
          control all the trust's substantial decisions.

          If you are a partnership or beneficial owner of an interest in a
partnership, your tax treatment may depend upon both your status and the
partnership's or the partners' status, as the case may be, and you are urged to
consult your tax advisor.

          If you are a beneficial owner of the notes or common stock not
included in the above list, you are a Non-U.S. Holder and you will generally be
subject to the rules described in "--Tax Consequences to Non-U.S. Holders"
below.

          Interest on Notes. You will be taxed on interest on a note as the
interest accrues or when you actually or constructively receive it, in
accordance with your method of accounting for U.S. federal income tax purposes.
We do not believe that the notes were issued with "original issue discount"
within the meaning of the Code.

          Conversion of Notes. The federal income tax treatment of a conversion
of Notes into shares of AmerisourceBergen Common Stock following the Merger is
unclear.

          The Internal Revenue Service has ruled that a conversion of notes for
stock of a parent corporation is not a taxable exchange when the parent became a
co-obligor on the notes with its subsidiary in connection with a prior merger,
when the addition of the parent corporation as a co-obligor (together with other
changes to the terms of the notes) was viewed as an exchange under Section 1001
of the Code of the subsidiary's notes for new notes. However, it is not clear
from the ruling whether the Internal Revenue Service's conclusion regarding the
tax-free treatment of the conversion depended upon its prior conclusion, in the
same ruling, that the prior note modification was a Section 1001 exchange. If
the treatment of the modification as a Section 1001 exchange is not a pre-
requisite to this conclusion, then the conversion of notes for AmerisourceBergen
common stock should not be a taxable disposition of the notes. If your
conversion of the notes into AmerisourceBergen common stock is not a taxable
event, your tax basis in any shares of common stock received would be equal to
the tax basis in any notes you surrender, and the holding period of those shares
would include the holding period for the notes you surrender.

          The notes (with AmerisourceBergen as co-obligor) should be viewed, for
federal income tax purposes, as merely a continuation of the AmeriSource notes
originally issued in December 2000, and the addition of AmerisourceBergen as co-
obligor should not result in a Section 1001 exchange of the notes.  As a result,
the notes might not be treated, for federal income tax purposes, as obligations
of AmerisourceBergen, despite its co-obligor status.  If that were the case, (i)
you would recognize gain or loss upon conversion of the notes into
AmerisourceBergen common stock, measured by the difference between the fair
market value of the common stock received and your tax basis in the notes
surrendered, and (ii) your tax basis in any shares of common stock received
would be equal to the fair market value of common stock on the date of the
conversion.

          If you receive cash in lieu of a fractional share of common stock, it
will be treated as a payment in exchange for the fractional share. You generally
will recognize capital gain or loss equal to the difference between the amount
of cash received and the amount of tax basis allocable to the fractional share.

          HOLDERS OF NOTES SHOULD CONSULT THEIR TAX ADVISORS WITH RESPECT TO THE
POSSIBLE CONSEQUENCES OF CONVERTING NOTES INTO SHARES OF AMERISOURCEBERGEN STOCK
FOLLOWING THE MERGER.

          Adjustment of Conversion Rate. The conversion rate of the notes is
subject to adjustment in certain circumstances. See "Description of the Notes--
Conversion Rights". Under Section 305(c) of the Code, adjustments that have the
effect of increasing or decreasing your proportionate interest in our assets or
earnings (for example, an adjustment following a distribution of property to our
stockholders) may in some circumstances give rise to a deemed distribution to
you. Similarly, a failure to adjust the conversion rate of the notes to reflect
a stock dividend or other event increasing the proportionate interest of
stockholders of outstanding stock can in some instances give rise to deemed
distributions to the stockholders. The deemed distributions will be treated as
dividends, returns of capital, or capital gains in accordance with the earnings
and profits rules discussed under "--Distributions on Common Stock" below.

          Liquidated Damages. We intend to take the position that the Liquidated
Damages described above under "Description of Notes--Registration Rights" will
be taxable to you as ordinary income in accordance with your method of
accounting for U.S. federal income tax purposes only as and if you become
entitled to or receive such Liquidated Damages, depending upon your method of
accounting. The IRS, however, may take a different position, which could affect
the timing of both your income and our deduction with respect to the Liquidated
Damages.

                                       31


          Distributions on Common Stock. Distributions that you receive on
common stock will be treated as dividends for U.S. federal income tax purposes
to the extent of current or accumulated earnings and profits as determined under
U.S. federal income tax principles. If you are a U.S. corporation, you may
qualify for the dividends received deduction. If you are not a corporation, you
are not entitled to a dividends received deduction.

          To the extent, if any, that you receive a distribution that would
otherwise constitute a dividend for U.S. federal income tax purposes but that
exceeds our current and accumulated earnings and profits, the excess will be
treated first as a non-taxable return of capital reducing your basis in the
common stock. To the extent that such a distribution also exceeds your basis in
the common stock, the excess will be treated as capital gain from the sale or
exchange of your common stock.

          Sale or Exchange of Notes or Common Stock. In general, subject to the
discussion under "--Market Discount" below, you will recognize capital gain or
loss on the sale, redemption, retirement or other disposition of a note measured
by the difference between the amount of cash and the fair market value of any
property received (except to the extent attributable to the payment of accrued
interest) and your adjusted tax basis in the note. In general, subject to the
discussion under "--Market Discount" below, if you receive common stock upon
conversion of a note, you will recognize gain or loss upon a subsequent sale,
exchange, redemption or other disposition of the common stock under rules
similar to the computation of gain or loss on disposition of the notes. However,
special rules may apply to a redemption of common stock which may result in the
proceeds of the redemption being treated as a dividend. In general, if you are
not a corporation, and have held the notes or common stock for more than one
year, you will be subject to a maximum federal tax rate of 20% on the capital
gains resulting from the disposition.

          Market Discount. If you acquire a note other than at original issue,
you may be affected by the "market discount" provisions of the Code. For this
purpose, market discount on a note generally equals the amount, if any, by which
the stated redemption price at maturity of the note immediately after you
acquire it exceeds your adjusted tax basis in the note. Subject to a de minimis
exception, if you acquire a note with market discount and later dispose of the
note, you must treat the gain as ordinary income to the extent of the "accrued
market discount" on the note when you dispose of it, unless you have made an
election to include accrued market discount in your income on a current basis.
In general, market discount will be treated as accruing from the time you buy it
over the remaining term of the note on a straight-line basis or, at your
election, under a constant yield method. If you acquire a note at a market
discount and do not elect to include accrued market discount income currently,
and you borrowed money (or maintained outstanding debt) to finance your purchase
of the note, you may be required to defer the deduction of a portion of the
interest on that debt until you dispose of the note in a taxable transaction. If
you acquire a note with market discount and receive common stock upon its
conversion, and you subsequently sell the common stock, you will be required to
treat as ordinary income the amount of accrued market discount that you had not
yet included in your income (if any) through the date of conversion.

          IRS Reporting and Backup Withholding. If you are not a corporation,
you may be subject to IRS reporting and backup withholding at a rate of 30.5%
(or such lesser rate applicable after 2001) on payments of interest on the
notes, dividends on common stock, and proceeds from the sale or other
disposition of the notes or common stock, if:

          .    you fail to furnish your taxpayer identification number ("TIN"),
               which ordinarily would be your social security number,

          .    you furnish an incorrect TIN,

          .    you are notified by the IRS that you have failed to properly
               report payments of interest or dividends, or

          .    under certain circumstances, you fail to certify, under penalties
               of perjury, that you have furnished a correct TIN and have not
               been notified by the IRS that you are subject to backup
               withholding.

          We will also institute backup withholding on payments made to you if
instructed to do so by the IRS. If you do not provide us with a correct TIN, you
may also be subject to penalties imposed by the IRS.

          You will be allowed to claim any amounts that we withhold as a credit
against your U.S. federal income tax liability, if any. If the amount of the
backup withholding exceeds your U.S. federal income tax liability, you may seek
a refund from the IRS, provided that you follow the requisite procedures. You
should consult your own tax advisor regarding your qualification for exemption
from backup withholding and the procedure for obtaining such an exemption, if
applicable.

                                       32


Tax Consequences to Non-U.S. Holders

          The following discussion applies to you if you are a Non-U.S. Holder.
Non-U.S. Holders' whose income or gain related to the notes or common stock is
effectively connected with the conduct of a U.S. trade or business will
generally be subject to the foregoing rules applicable to U.S. Holders, subject
to applicable treaty relief.

          Payments of interest. Generally, if you or someone acting on your
behalf receive payments of interest (including for this purpose, any Liquidated
Damages) on the notes, the payments will not be subject to U.S. federal
withholding tax if:

          .        you do not actually or constructively own 10% or more of the
                   total combined voting power of all classes of our stock;

          .        you are not (a) a controlled foreign corporation for U.S.
                   federal income tax purposes that is related to us through
                   stock ownership or (b) a bank that received the note on an
                   extension of credit made pursuant to a loan agreement entered
                   into in the ordinary course of its trade or business; and

          .        you provide a statement, signed under penalties of perjury,
                   that includes your name and address and certifies that you
                   are not a U.S. person.

          If you cannot satisfy these requirements, you will be subject to U.S.
federal withholding tax at a rate of 30% unless you qualify for a reduced rate
under a tax treaty or under certain other special circumstances. If you qualify
for a reduced withholding rate, you will have to declare that you are so
qualified by providing us with the appropriate form, signed under penalties of
perjury.

          Adjustment of Conversion Rate. The conversion rate of the notes may be
adjusted in certain circumstances. See "Description of Notes--Conversion
Rights". Any such adjustment could give rise to a deemed distribution to you in
the same manner as was described for U.S. Holders. See "Tax Consequences to U.S.
Holders--Adjustment of Conversion Rate" above. If so, the deemed distribution
would be subject to the rules described below regarding withholding of U.S.
federal income tax on dividends. See "--Distributions on Common Stock" below.

          Distributions on Common Stock. If you receive distributions on common
stock, they will be dividends for U.S. federal income tax purposes to the extent
of our current or accumulated earnings and profits, as determined under U.S.
federal income tax principles, and will be subject to U.S. federal withholding
tax at a rate of 30% unless you qualify for a reduced rate under a tax treaty or
under certain other special circumstances. If you qualify for a reduced
withholding rate, you will have to declare that you are so qualified by
providing us with the appropriate form, signed under penalties of perjury.

          Sale or Exchange of Notes or Common Stock. In general, you will not be
subject to U.S. federal withholding tax on gain recognized upon the sale or
other disposition (including a redemption) of a note or common stock received
upon conversion thereof unless:

          .        you are a nonresident alien individual present in the United
                   States for 183 days or more in the taxable year in which gain
                   is realized, and certain other conditions are satisfied;

          .        you are subject to tax pursuant to the provisions of U.S. tax
                   law applicable to certain U.S. expatriates; or

          .        we are or have been a United States real property holding
                   corporation ("USRPHC") for U.S. federal income tax purposes
                   at any time within the shorter of the five year period
                   preceding the disposition or your holding period.

          We believe we are not presently, and are not likely to become, a
USRPHC.

          U.S. Estate Tax. If you own notes when you die and you are not a
citizen or resident (as specifically defined for U.S. federal estate tax
purposes) of the United States at the time of your death, the notes will not be
includible in your

                                       33


gross estate for U.S. federal estate tax purposes, provided that, at the time of
your death, you do not own, actually or constructively, 10% or more of the total
combined voting power of all classes of our stock, and any payments with respect
to the notes would not have been effectively connected with your conduct of a
trade or business in the United States. However, the common stock you own will
be includible in your gross estate for U.S. federal estate tax purposes as a
result of your death, and subject to applicable treaty limitations, may be
subject to U.S. federal estate tax.

         IRS Reporting and Backup Withholding. We must report annually to the
IRS and to you any interest and dividends paid with respect to any notes or
common stock that you hold, and whether they are subject to U.S. federal
withholding tax or exempt from such tax under an applicable treaty or the Code.
We also report to the IRS and to you any income that we paid to you and that is
exempt from federal withholding tax because it is effectively connected with
your U.S. trade or business even though that "effectively connected income" is
exempt from withholding, you will be required to pay U.S. federal income tax on
it. However, you will not be subject to IRS reporting or backup withholding if
we have received the appropriate forms from you or on your behalf and provided
that we do not have actual knowledge that you are in fact a U.S. Holder. If we
pay the proceeds from the disposition of notes or common stock to or through the
U.S. office of any broker, the payment will be subject to IRS reporting and
possibly backup withholding unless you certify as to your non-U.S. status under
penalties of perjury or otherwise establish an exemption, provided that the
broker does not have actual knowledge that you are in fact a U.S. Holder or that
the conditions of any other exemption are not, in fact, satisfied. If we pay any
proceeds from the distribution of a note or common stock to or through a non-
U.S. office of a non-U.S. broker that is not a "U.S. related person", those
proceeds will not be subject to IRS reporting or backup withholding. For this
purpose, a "U.S. related person" is:

         .     a "controlled foreign corporation" for U.S. federal income tax
               purposes;

         .     a person 50% or more of whose gross income from all sources for
               the three-year period ending with the close of its taxable year
               preceding the payment (or for such part of the period that the
               broker has been in existence) is derived from activities that are
               effectively connected with the conduct of a U.S. trade or
               business, or

         .     a foreign partnership, if at any time during its tax year, one or
               more of its partners are U.S. persons (as defined in the
               Regulations) who in the aggregate hold more than 50% of the
               income or capital interest in the partnership, or if at any time
               during the tax year the partnership is engaged in a U.S. trade or
               business.

         If we pay proceeds from the disposition of notes or common stock to or
through a non-U.S. office of a broker that is a U.S. related person, the
Regulations require us to report on the payment unless the broker has
documentary evidence in its files that you are a Non-U.S. Holder and the broker
has no knowledge to the contrary. Backup withholding will not apply to such
payments, unless we have actual knowledge that you are a U.S. Person.

                         DESCRIPTION OF CAPITAL STOCK


Authorized Capital Stock

         Total Shares. We are authorized to issue a total of 310,000,000 shares
of capital stock consisting of:

         .     300,000,000 shares of common stock, par value $0.01 per share;
               and

         .     10,000,000 shares of preferred stock, par value $0.01 per share.

         Listing. The common stock trades on the New York Stock Exchange under
the symbol "ABC." No other capital stock of AmerisourceBergen is listed.

         Preemptive Rights. The holders of our common stock and preferred stock
have no preemptive rights to purchase or subscribe for any stock or other
securities of AmerisourceBergen.

                                       34


Common Stock

         Voting Rights. Each outstanding share of common stock is entitled to
one vote per share. The holders of common stock have the exclusive right to vote
for the election of directors and for all other purposes as provided by law.

         Dividends. Subject to the rights of holders of preferred stock, holders
of common stock are entitled to receive ratably on a per share basis such
dividends and other distributions in cash, stock or property of
AmerisourceBergen as may be declared by the board of directors from time to time
out of the legally available assets or funds of AmerisourceBergen. We currently
intend to pay quarterly dividends on its common stock of $0.025 per share.

         Liquidation. Subject to the rights of holders of preferred stock, in
the event of the voluntary or involuntary liquidation, dissolution or winding up
of AmerisourceBergen, holders of common stock are entitled to receive all of the
remaining assets of AmerisourceBergen available for distribution to its
stockholders.

Preferred Stock

         General. Our board of directors is authorized to provide for the
issuance of shares of preferred stock in one or more series with various
designations, preferences, and relative, participating, optional or other
special rights and qualifications, limitations or restrictions.

         Voting. Except as required by law, or as otherwise provided by the
board of directors, the holders of preferred stock have no voting rights and
will not be entitled to any notice of meeting of stockholders.

         Dividends. Holders of preferred stock are entitled to receive, when
declared by the board of directors, out of legally available funds, dividends at
the rates fixed by the board of directors for the respective series of preferred
stock, and no more, before any dividends will be declared and paid, or set apart
for payment, on AmerisourceBergen common stock with respect to the same dividend
period.

         Liquidation. In the event of the voluntary or involuntary liquidation,
dissolution or winding up of AmerisourceBergen, holders of each series of
preferred stock are entitled to receive the amount fixed for such series plus,
in the case of any series on which dividends will have been determined by the
board of directors to be cumulative, an amount equal to all dividends
accumulated and unpaid to the date of final distribution whether or not earned
or declared before any distribution shall be paid, or set aside for payment, to
holders of common stock.

         Redemption. At the option of our board of directors, we may redeem all
or part of the shares of any series of preferred stock on such terms and
conditions fixed in the applicable preferred stock certificate of designation
for such series.

Stockholders Rights Plans

         AmerisourceBergen.  On August __, 2001, AmerisourceBergen adopted a
stockholder rights plan pursuant to a rights agreement with Mellon Investor
Services LLC, as rights agent.  Set forth below is a summary of the material
provisions of the rights agreement.  The summary does not include a complete
description of all of the terms of the rights agreement.

         Exercisability of Rights.  Under the AmerisourceBergen rights
agreement, one right, referred to as an AmerisourceBergen right, attaches to
each share of AmerisourceBergen common stock outstanding and, when exercisable,
entitles the registered holder to purchase from AmerisourceBergen one one-
hundredth of a share of AmerisourceBergen Series A preferred stock at an initial
purchase price of $275, subject to customary antidilution adjustments.

         The AmerisourceBergen rights will not become exercisable until the
earlier of:

         .  10 business days following a public announcement that a person has
            become the beneficial owner of 15% or more of the AmerisourceBergen
            common stock then outstanding; and

         .  10 business days, or such later date as may be determined by the
            board of directors of AmerisourceBergen, following the commencement
            of a tender offer or exchange offer that would result in a person
            becoming the beneficial owner of 15% or more of the
            AmerisourceBergen common stock then outstanding.

         Series A Preferred Stock. In connection with the creation of the
AmerisourceBergen rights, the board of directors of AmerisourceBergen authorized
the issuance of 3,000,000 shares of AmerisourceBergen preferred stock designated
as AmerisourceBergen Series A preferred stock.

         AmerisourceBergen has designed the dividend, liquidation, voting and
redemption features of the AmerisourceBergen Series A preferred stock so that
the value of one one-hundredth of a share of AmerisourceBergen Series A
preferred stock approximates the value of one share of AmerisourceBergen common
stock.  Shares of AmerisourceBergen Series A preferred stock may only be
purchased after the AmerisourceBergen rights have become exercisable.

         "Flip In" Feature. In the event a person becomes the beneficial owner
of 15% or more of the AmerisourceBergen common stock outstanding, each holder of
an AmerisourceBergen right, except for such acquiring person, will have the
right to acquire, upon exercise of the AmerisourceBergen right, instead of one
one-hundredth of a share of AmerisourceBergen Series A preferred stock, shares
of AmerisourceBergen Series A preferred stock having a value equal to twice the
then current purchase price of each one one-hundredth share of AmerisourceBergen
Series A preferred stock. For example, if we assume that the initial purchase

                                      35


price of $275 is in effect on the date that the flip-in feature of the
AmerisourceBergen rights is triggered, any holder of an AmerisourceBergen right,
except for the person that has become the beneficial owner of 15% or more of the
AmerisourceBergen common stock then outstanding, may exercise his or her
AmerisourceBergen right by paying to AmerisourceBergen $275 in order to receive
from AmerisourceBergen shares of AmerisourceBergen Series A preferred stock
having a value equal to $550.

         "Flip Over" Feature. In the event that following a public announcement
a person has become the beneficial owner of 15% or more of the AmerisourceBergen
common stock then outstanding:

         .  AmerisourceBergen merges into another entity,

         .  another entity merges into AmerisourceBergen, or

         .  AmerisourceBergen sells more than 50% of its assets or earning
            power,

then each holder of an AmerisourceBergen right, except for such person that is
the beneficial owner of 15% or more of the AmerisourceBergen common stock then
outstanding, may have the right to receive, upon exercise of the
AmerisourceBergen right, the number of shares of the acquiring company's capital
stock with the greatest voting power having a value equal to twice the then
current purchase price of each one one-hundredth share of AmerisourceBergen
Series A preferred stock.

         "Exchange" Feature. At any time after a person becomes the beneficial
owner of 15% or more, but, in certain circumstances, less than 50%, of the
AmerisourceBergen common stock then outstanding, the board of directors of
AmerisourceBergen may, at its option, exchange all or part of the
AmerisourceBergen rights, except for those held by such acquiring person, for
AmerisourceBergen common stock at an exchange ratio of one one-hundredth of a
share of AmerisourceBergen common stock for each AmerisourceBergen right,
subject to adjustment, and cash instead of fractional shares, if any. Use of
this exchange feature means that eligible AmerisourceBergen rights holders will
not have to pay a purchase price before receiving shares of AmerisourceBergen
Series A preferred stock.

         Redemption of Rights. At any time prior to the earlier to occur of:

         .  10 business days following a public announcement that a person has
            become the beneficial owner of 15% or more of the AmerisourceBergen
            common stock then outstanding, or

         .  August __, 2011

the board of directors of AmerisourceBergen may redeem all of the
AmerisourceBergen rights at a redemption price of $0.01 per right, subject to
adjustment. The right to exercise the AmerisourceBergen rights will terminate
upon redemption, and at that time, the holders of the AmerisourceBergen rights
will have the right to receive only the redemption price for each
AmerisourceBergen right they hold.

         Amendment of Rights. At any time prior to the earlier to occur of:

         (a)  10 business days following a public announcement that a person has
              become the beneficial owner of 15% or more of the
              AmerisourceBergen common stock then outstanding; and

         (b)  10 business days, or such later date as may be determined by the
              board of directors of AmerisourceBergen, following the
              commencement of a tender offer or exchange offer that would result
              in a person becoming the beneficial owner of 15% or more of the
              AmerisourceBergen common stock then outstanding,

the terms of the existing AmerisourceBergen rights agreement may be amended by
the board of directors of AmerisourceBergen without the approval of the holders
of the rights.  However, after the earlier to occur of (a) and (b) above, the
rights agreement may not be amended in any manner that would adversely affect
the interests of the holders of the AmerisourceBergen rights, excluding the
interests of the acquiror.

         Termination of Rights. If not previously exercised, the
AmerisourceBergen rights will expire on August __, 2011 unless AmerisourceBergen
earlier redeems or exchanges the AmerisourceBergen rights or extends the
expiration date as provided in the rights agreement.

         Anti-Takeover Effects. The AmerisourceBergen rights have anti-takeover
effects.  Once the AmerisourceBergen rights have become exercisable, in most
cases the AmerisourceBergen rights will cause substantial dilution to a person
that attempts to acquire or merge with AmerisourceBergen.  Accordingly, the
existence of the AmerisourceBergen rights may deter potential acquirors from
making a takeover proposal or a tender offer.  The AmerisourceBergen rights
should not interfere with any merger or other business combination approved by
the board of directors of AmerisourceBergen since AmerisourceBergen may redeem
the AmerisourceBergen rights.


                            SELLING SECURITYHOLDERS

         AmeriSource originally issued the notes in a private placement in
December, 2000. The initial purchasers of the notes have advised AmeriSource
that the notes were resold in transactions exempt from the registration
requirements of the Securities Act to "qualified institutional buyers", as
defined in Rule 144A of the Securities Act. These subsequent purchasers, or
their transferees, pledgees, donees or successors, may from time to time offer
and sell any or all of the notes and/or shares of the common stock issuable upon
conversion of the notes pursuant to this prospectus.

                                      36




         The notes and the shares of common stock issuable upon conversion of
the notes have been registered in accordance with the registration rights
agreement. Pursuant to the registration rights agreement, we are required to
file a registration statement with regard to the notes and the shares of
AmerisourceBergen common stock issuable upon conversion of the notes and to keep
the registration statement effective until the earlier of:

         (1)   the sale of all the securities registered under the registration
               rights agreement;

         (2)   the expiration of the holding period applicable to these
               securities under Rule 144(k) under the Securities Act with
               respect to persons who are not our affiliates; and

                                      37



         (3)   two years from the date the notes were originally issued.

         The selling securityholders may choose to sell notes and/or the shares
of common stock issuable upon conversion of the notes from time to time. See
"Plan of Distribution".

         The following table sets forth:

         (1)   the name of each selling securityholder who has provided
               AmeriSource with notice as of the date of this prospectus
               pursuant to the registration rights agreement of their intent to
               sell or otherwise dispose of notes and/or shares of common stock
               issuable upon conversion of the notes pursuant to the
               registration statement,

         (2)   the principal amount of notes and the number of shares of
               AmerisourceBergen common stock issuable upon conversion of the
               notes which they may sell from time to time pursuant to the
               registration statement, and

         (3)   the amount of outstanding notes and AmerisourceBergen common
               stock beneficially owned by the selling securityholder prior to
               the offering, assuming no conversion of the notes.

         To our knowledge, no selling securityholder nor any of its affiliates
has held any position or office with, been employed by or otherwise has had any
material relationship with us or our affiliates during the three years prior to
the date of this prospectus.

         A selling securityholder may offer all or some portion of the notes and
shares of the common stock issuable upon conversion of the notes. Accordingly,
no estimate can be given as to the amount or percentage of notes or our common
stock that will be held by the selling securityholders upon termination of sales
pursuant to this prospectus. In addition, the selling securityholders identified
below may have sold, transferred or disposed of all or a portion of their notes
since the date on which they provided the information regarding their holdings
in transactions exempt from the registration requirements of the Securities Act.

         The information contained under the column heading "Shares That May be
Sold" assumes conversion of the full amount of the notes held by the holder at
the initial rate of 18.8791 shares of common stock per each $1,000 principal
amount of notes.



                                                             Amount of                           Shares of
                                                            Notes Owned        Amount of        Common Stock
                                                              Before           Notes that       Owned Before        Shares That
                        Name                                 Offering         May be Sold         Offering          May be Sold
-----------------------------------------------------      -------------     -------------    ------------------   -------------
                                                                                                       
AAM Zazove Institutional Income Fund, L.P............      $   900,000       $     900,000              0               16,991
Aftra Health Fund....................................      $   600,000       $     600,000              0               11,327
AIG/National Union Fire Insurance....................      $   300,000       $     300,000              0                5,664
Alpine Associates....................................      $ 2,850,000       $   2,850,000              0               53,805
Alpine Partners, L.P.................................      $   550,000       $     550,000              0               10,384
American Motorist Insurance Company..................      $   462,000       $     462,000              0                8,722
American Samoa Government............................      $    40,000       $      40,000              0                  755
AmSouth Bank, custodian for AmSouth Equity
    Income Fund......................................      $ 2,890,000       $   2,890,000              0               54,561
AmSouth Bank, custodian for AmSouth Variable
    Equity Income Fund...............................      $ 1,570,000       $   1,570,000              0               29,640
Arapahoe County Colorado.............................      $    44,000       $      44,000              0                  831
Arbitex Master Fund, L.P.............................      $ 2,000,000       $   2,000,000              0               37,758
Arkansas PERS........................................      $   990,000       $     990,000              0               18,690
Associated Electric & Gas Insurance Services
    Limited..........................................      $   500,000       $     500,000              0                9,440
Aventis Pension Master Trust.........................      $   110,000       $     110,000              0                2,077
Banc of America Securities L.L.C. (1)................      $    35,000       $      35,000              0                  661


                                      38



                                                                                                       
Bank Austria Cayman Islands, Ltd.....................      $ 9,330,000       $   9,330,000              0              176,142
BBT Fund, L.P........................................      $10,000,000       $  10,000,000              0              188,791
Bear, Stearns & Company, Inc.........................      $ 2,500,000       $   2,500,000              0               47,198
Boilermaker-Blacksmith Pension Trust.................      $   685,000       $     685,000              0               12,932
Boilermakers Blacksmith Pension Trust................      $ 1,380,000       $   1,380,000              0               26,053
BP Amoco Corporation Master Trust for
    Employee Pension Plans...........................      $ 8,240,000       $   8,240,000              0              155,564
BP Amoco PLC Master Trust............................      $ 1,669,000       $   1,669,000              0               31,509
British Virgin Island Social Security Board..........      $    33,000       $      33,000              0                  623
BS Debt Income Fund - Class A........................      $    10,000       $      10,000              0                  189
BT Opportunity.......................................      $ 4,000,000       $   4,000,000              0               75,516
BT Strategy..........................................      $ 1,000,000       $   1,000,000              0               18,879
Calamos Convertible Fund - Calamos
    Investment Trust.................................      $ 2,430,000       $   2,430,000              0               45,876
Calamos Convertible Growth and Income
     Fund - Calamos Investment Trust.................      $ 1,520,000       $   1,520,000              0               28,696
Calamos Convertible Portfolio - Calamos
    Advisors Trust...................................      $   100,000       $     100,000              0                1,888
Calamos Global Convertible Fund - Calamos
    Investment Trust.................................      $   305,000       $     305,000              0                5,758
Castle Convertible Fund, Inc.........................      $   500,000       $     500,000              0                9,440
Chrysler Corporation Master Retirement
    Trust............................................      $ 3,110,000       $   3,110,000              0               58,714
Citi Cap Arb Fund....................................      $   689,000       $     689,000              0               13,008
City of Albany Pension Plan..........................      $    65,000       $      65,000              0                1,227
City of Knoxville Pension System.....................      $   150,000       $     150,000              0                2,832
City of New Orleans..................................      $   172,000       $     172,000              0                3,247
City University of New York..........................      $   112,000       $     112,000              0                2,114
Clarica Life Insurance Co. - U.S.....................      $   275,000       $     275,000              0                5,192
Continental Assurance Company........................      $ 2,480,000       $   2,480,000              0               46,820
Continental Assurance Company on behalf of
    ITS..............................................       $3,480,000       $   3,480,000              0               65,699
Convertible Arb Qib..................................      $ 1,300,000       $   1,300,000              0               24,543
De Am Convertible Arbitrage Fund.....................      $ 5,250,000       $   5,250,000              0               99,115
Delaware PERS........................................      $ 1,525,000       $   1,525,000              0               28,791
Delta Air Lines Master Trust.........................      $ 1,285,000       $   1,285,000              0               24,260
Delta Air Lines Master Trust.........................      $ 1,275,000       $   1,275,000              0               24,071
Delta Pilots D & S Trust.............................      $   215,000       $     215,000              0                4,059
Delta Pilots Disability and Survivorship Trust.......      $   375,000       $     375,000              0                7,080
Diversified Arb Fund.................................      $ 2,425,000       $   2,425,000              0               45,782
Drury University.....................................      $    40,000       $      40,000              0                  755
Employee Benefit Convertible Securities Fund.........      $   180,000       $     180,000              0                3,398
Enron North America, Corp............................      $ 2,000,000       $   2,000,000              0               37,758
F.R. Convertible Securities Fund.....................      $    80,000       $      80,000              0                1,510
Family Service Life Insurance Company................      $   100,000       $     100,000              0                1,888
Federated Equity Income Fund, Inc....................      $31,470,000       $  31,470,000              0              594,125
Federated Insurance Series on behalf of
    Federated Equity Income Fund II..................      $ 1,200,000       $   1,200,000              0               22,655
Fidelity Financial Trust:  Fidelity Convertible
    Securities Fund..................................      $ 4,300,000       $   4,300,000              0               81,180


                                      39




                                                              Amount                                 Shares
                                                           Notes Owned          Amount of         Common Stock
                                                              Before            Notes that        Owned Before     Shares That
                     Name                                    Offering          May be Sold          Offering       May be Sold
-----------------------------------------------------     -------------      ---------------     -------------    ------------
                                                                                                      
General Motors Investment Management
    Corp.............................................      $ 4,000,000       $   4,000,000             0             75,516
General Motors Welfare Benefit Trust Arb
    Fund.............................................      $   375,000       $     375,000             0              7,080
Goldman, Sachs & Company(1)(2).......................      $12,450,000       $  12,450,000             0            235,045
Grady Hospital Foundation............................      $    99,000       $      99,000             0              1,869
Greek Catholic Union.................................      $    20,000       $      20,000             0                378
Greek Catholic Union II..............................      $    15,000       $      15,000             0                283
Guardian Life Insurance Company of America...........      $ 4,700,000       $   4,700,000             0             88,732
Guardian Pension Trust...............................      $   200,000       $     200,000             0              3,776
H.K. Porter Company, Inc.............................      $    20,000       $      20,000             0                378
HFR Convertible Arbitrage Account....................      $   200,000       $     200,000             0              3,776
Hotel Union and Hotel Industry of Hawaii.............      $   339,000       $     339,000             0              6,400
ICI American Holdings................................      $   825,000       $     825,000             0             15,575
Independence Blue Cross..............................      $   120,000       $     120,000             0              2,265
Island Holdings......................................      $    15,000       $      15,000             0                283
Jefferies & Company Inc..............................      $   200,000       $     200,000             0              3,776
KBC Financial Products USA...........................      $   500,000       $     500,000             0              9,440
Kemper Foundation....................................      $   100,000       $     100,000             0              1,888
Kentfield Trading, Ltd...............................      $11,070,000       $  11,070,000             0            208,992
Kettering Medical Center Funded
    Depreciation Account.............................      $    45,000       $      45,000             0                850
Knoxville Utilities Board Retirement System..........      $   100,000       $     100,000             0              1,888
Lancer Securities Cayman Ltd.........................      $   250,000       $     250,000             0              4,720
Lehman Brothers, Inc.................................      $    70,000       $      70,000             0              1,322
Lincoln National Convertible Securities Fund.........      $ 1,600,000       $   1,600,000             0             30,207
Lipper Convertible Series II, L.P....................      $ 2,000,000       $   2,000,000             0             37,758
Lipper Convertibles, L.P.............................      $ 8,850,000       $   8,850,000             0            167,080
Lipper Convertibles, L.P. (Class B)..................      $   581,000       $     581,000             0             10,969
Lipper Offshore Convertibles, L.P. ..................      $ 3,000,000       $   3,000,000             0             56,637
Lipper Offshore Convertibles, L.P. #2................      $   419,000       $     419,000             0              7,910
Local Initiatives Support Corporation................      $    53,000       $      53,000             0              1,001
Louisiana Workers' Compensation Corp.................      $   100,000       $     100,000             0              1,888
Lumbermens...........................................      $   750,000       $     750,000             0             14,159
Mainstay Convertible Fund............................      $ 8,795,000       $   8,795,000             0            166,042
Mainstay VP Convertible Portfolio....................      $ 2,250,000       $   2,250,000             0             42,478
Market Neutral Arb Fund..............................      $ 1,002,000       $   1,002,000             0             18,917
McMahan Securities Co. L.P...........................      $ 1,020,000       $   1,020,000             0             19,257
Merrill Lynch Insurance Group (3)....................      $    98,000       $      98,000             0              1,850
Miller Tabak Roberts Securities, LLC.................      $   170,000       $     170,000             0              3,209
Morgan Stanley & Co..................................      $ 1,528,000       $   1,528,000             0             28,847
Motion Picture Industry Health Plan - Active
    Member Fund......................................      $   435,000       $     435,000             0              8,212
Motion Picture Industry Health Plan - Retiree
    Member Fund......................................      $   145,000       $     145,000             0              2,737
Municipal Employees..................................      $   140,000       $     140,000             0              2,643
Muni Strategy Arbitrage..............................      $ 4,447,000       $   4,447,000             0             83,955
Nabisco Holdings.....................................      $    41,000       $      41,000             0                774
Nalco Chemical Company...............................      $   100,000       $     100,000             0              1,888
Nations Convertible Securities Fund..................      $ 4,745,000       $   4,745,000             0             89,581


                                      40





                                                              Amount                                 Shares
                                                           Notes Owned          Amount of         Common Stock
                                                              Before            Notes that        Owned Before     Shares That
                     Name                                    Offering          May be Sold          Offering       May be Sold
-----------------------------------------------------     -------------      ---------------     -------------    ------------
                                                                                                      
Nationwide Separate Account Trust on
    behalf of Nationwide Equity Income Fund..........      $   640,000       $     640,000             0             12,083
New Orleans Firefighters Pension/Relief Fund.........      $   144,000       $     144,000             0              2,719
New York Life Insurance Company......................      $ 7,200,000       $   7,200,000             0            135,930
New York Life Insurance Company and
    Annuity Corporation..............................      $   800,000       $     800,000             0             15,103
New York Life Separate Account #7....................      $ 1,200,000       $   1,200,000             0             22,655
1976 Distribution Trust FBO Jane A. Lauder...........      $    17,000       $      17,000             0                321
1976 Distribution Trust FBO
    Lauder/Zinterhofer...............................      $    18,000       $      18,000             0                340
Occidental Petroleum Corporation.....................      $   178,000       $     178,000             0              3,360
OCM Convertible Trust................................      $ 1,845,000       $   1,845,000             0             34,832
Ohio Bureau of Workers Compensation..................      $   150,000       $     150,000             0              2,832
Ohio National Fund, Inc. on behalf of
    Equity Income Portfolio..........................      $   120,000       $     120,000             0              2,265
Pacific Life Insurance Company.......................      $   500,000       $     500,000             0              9,440
Palladin Securities L.L.C............................      $   500,000       $     500,000             0              9,440
Partner Reinsurance Company Ltd......................      $   750,000       $     750,000             0             14,159
PGEP IV..............................................      $    80,000       $      80,000             0              1,510
Policemen and Firemen Retirement System of
    the City of Detroit..............................      $   500,000       $     500,000             0              9,440
Port Authority of Allegheny County
    Retirement and Disability Allowance Plan
    for the Employees represented by Local 85
    of the Amalgamated Transit Union.................      $   725,000       $     725,000             0             13,687
Primerica Life Insurance Company.....................      $   869,000       $     869,000             0             16,406
Pro Mutual...........................................      $   560,000       $     560,000             0             10,572
Ramius Capital Group Holdings, Ltd...................      $   600,000       $     600,000             0             11,327
Ramius Capital Group Latitude Master Fund............      $ 1,500,000       $   1,500,000             0             28,319
Raytheon Master Pension Trust........................      $   506,000       $     506,000             0              9,553
Regence Oregon.......................................      $   166,000       $     166,000             0              3,134
Regence Utah.........................................      $    56,000       $      56,000             0              1,057
Regence Washington...................................      $   278,000       $     278,000             0              5,248
RJR Reynolds.........................................      $    86,000       $      86,000             0              1,624
Rockhaven Fund.......................................      $    80,000       $      80,000             0              1,510
Rockhaven Premier Dividend Fund......................      $   690,000       $     690,000             0             13,027
SB Convertible Fund..................................      $ 1,000,000       $   1,000,000             0             18,879
SCI Endowment Care Common Trust Fund -
    National Fiduciary Services......................      $    55,000       $      55,000             0              1,038
SCI Endowment Care Common Trust Fund -
    Suntrust.........................................      $    85,000       $      85,000             0              1,605
SG Cowen Securities, Inc.                                  $ 2,040,000       $   2,040,000             0             38,513
Shell Pension Trust..................................      $   393,000       $     393,000             0              7,419
SPT..................................................      $   570,000       $     570,000             0             10,761
Starvest Combined Portfolio..........................      $   310,000       $     310,000             0              5,853
State Employees' Retirement Fund of the
    State of Delaware................................      $ 1,570,000       $   1,570,000             0             29,640
State of Connecticut Combined Investment
    Funds............................................      $ 4,120,000       $   4,120,000             0             77,782
State of Maryland Retirement System..................      $ 2,358,000       $   2,358,000             0             44,517
State of Oregon/Equity...............................      $ 4,950,000       $   4,950,000             0             93,452


                                      41




                                                              Amount                                 Shares
                                                           Notes Owned          Amount of         Common Stock
                                                              Before            Notes that        Owned Before     Shares That
                     Name                                    Offering          May be Sold          Offering       May be Sold
-----------------------------------------------------     -------------      ---------------     -------------    ------------
                                                                                                      
The Class 1C Company.................................      $ 2,000,000       $   2,000,000             0             37,758
The Dow Chemical Company Employees'
    Retirement Plan..................................      $ 1,400,000       $   1,400,000             0             26,431
The Estate of James Campbell.........................      $   285,000       $     285,000             0              5,381
The Fondren Foundation...............................      $    50,000       $      50,000             0                944
The Grable Foundation................................      $    86,000       $      86,000             0              1,624
The Travelers Indemnity Company......................      $ 2,565,000       $   2,565,000             0             48,425
The Travelers Insurance Company......................      $   166,000       $     166,000             0              3,134
The Travelers Insurance Company-Life.................      $ 1,474,000       $   1,474,000             0             27,828
The Travelers Insurance Company Separate
    Account TLAC.....................................      $   166,000       $     166,000             0              3,134
The Travelers Life and Annuity Company...............      $   176,000       $     176,000             0              3,323
Travelers Series Managed Assets Trust................      $    75,000       $      75,000             0              1,416
Travelers Series Trust Convertible Bond
    Portfolio........................................      $   225,000       $     225,000             0              4,248
UBKAM Arbitrage Fund Ltd.............................      $ 1,500,000       $   1,500,000             0             28,319
UBKAM Global High Yield Fund Ltd.....................      $ 1,500,000       $   1,500,000             0             28,319
UBS O'Connor, LLC F/B/O Global Equity................      $ 4,000,000       $   4,000,000             0             75,516
UBS Warburg, LLC.....................................      $ 6,800,000       $   6,800,000             0            128,378
Unifi, Inc. Profit Sharing Plan and Trust............      $    70,000       $      70,000             0              1,322
United Food and Commercial Workers Local
    1262 and Employers Pension Fund..................      $   330,000       $     330,000             0              6,230
United Healthcare Insurance Company..................      $   450,000       $     450,000             0              8,496
Value Line Convertible Fund, Inc.....................      $   500,000       $     500,000             0              9,440
Van Kampen Harbor Fund...............................      $ 4,000,000       $   4,000,000       628,000(4)          75,516
Van Waters & Rogers, Inc. Retirement Plan............      $   195,000       $     195,000             0              3,681
Vanguard Convertible Securities Fund, Inc............      $ 4,450,000       $   4,450,000             0             84,012
Zeneca AG Products, Inc..............................      $   150,000       $     150,000             0              2,832
Zeneca Holdings Trust................................      $   375,000       $     375,000             0              7,080
Zurich HFR Master Hedge Fund Index Ltd...............      $    80,000       $      80,000             0              1,510
Zurich Institutional Benchmarks Master Fund
    Ltd. (Global)....................................      $ 1,100,000       $   1,100,000             0             20,767
Unknown (5)..........................................      $17,810,000       $  17,810,000            --            336,237


______________

(1)  One of the initial purchasers.
(2)  Goldman, Sachs & Company acted as financial advisor to AmeriSource in its
     merger transaction with Bergen.
(3)  Merrill Lynch, Pierce, Fenner & Smith Incorporated acted as financial
     advisor to Bergen in its merger transaction with AmeriSource.
(4)  All of these shares of common stock are held by entities affiliated with
     the Van Kampen Harbor Fund.
(5)  The name "Unknown" represents the remaining selling securityholders. We are
     unable to provide the names of these securityholders because certain of
     these notes are currently evidenced by a global note which has been
     deposited with DTC and registered in the name of CEDE & Co. as DTC's
     nominee.

         If, after the date of this prospectus, a securityholder notifies us
pursuant to the registration rights agreement of its intent to dispose of notes
pursuant to the registration statement, we may supplement this prospectus to
include that information.

                                       42





                              PLAN OF DISTRIBUTION

     We are registering the notes and the shares of our common stock issuable
upon conversion of the notes to permit public secondary trading of these
securities by the holders from time to time after the date of this prospectus.
AmeriSource has agreed, among other things, to bear all expenses, other than
underwriting discounts and selling commissions, in connection with the
registration and sale of the notes and the shares of our common stock issuable
upon conversion of the notes covered by this prospectus.

     We will not receive any of the proceeds from the offering of the notes or
the shares of AmerisourceBergen common stock issuable upon conversion of the
notes by the selling securityholders. The notes and shares of common stock
issuable upon conversion of the notes may be sold from time to time directly by
any selling securityholder or, alternatively, through underwriters, broker-
dealers or agents. If notes or shares of common stock issuable upon conversion
of the notes are sold through underwriters or broker-dealers, the selling
securityholder will be responsible for underwriting discounts or commissions or
agents' commissions.

     The notes or shares of common stock issuable upon conversion of the notes
may be sold:

     .    in one or more transactions at fixed prices,

     .    at prevailing market prices at the time of sale,

     .    at varying prices determined at the time of sale or

     .    at negotiated prices.

     These sales may be effected in transactions, which may involve block trades
or transactions in which the broker acts as agent for the seller and the buyer:

     .    on any national securities exchange or quotation service on which the
          notes or shares of common stock issuable upon conversion of the notes
          may be listed or quoted at the time of sale,

     .    in the over-the-counter market,

     .    in transactions otherwise than on a national securities exchange or
          quotation service or in the over-the-counter market or through the
          writing of options.

     In connection with sales of the notes or shares of common stock issuable
upon conversion of the notes or otherwise, any selling securityholder may:

     .    enter into hedging transactions with broker-dealers, which may
          in turn engage in short sales of the notes or shares of common
          stock issuable upon conversion of the notes in the course of
          hedging the positions they assume,

     .    sell short and deliver notes or shares of common stock issuable upon
          conversion of the notes to close out the short positions or

     .    loan or pledge notes or shares of common stock issuable upon
          conversion of the notes to broker-dealers that in turn may
          sell the securities.

     The outstanding AmerisourceBergen common stock is publicly traded on the
New York Stock Exchange. The initial purchasers of the notes have advised us
that certain of the initial purchasers are making and currently intend to
continue making a market in the notes; however, they are not obligated to do so
and any market-making of this type may be discontinued at any time without
notice, in the sole discretion of the initial purchasers. We do not intend to
apply for listing of the notes on the New York Stock Exchange or any securities
exchange. Accordingly, we cannot assure that any trading market will develop or
have any liquidity.

     The selling securityholders and any broker-dealers, agents or underwriters
that participate with the selling securityholders in the distribution of the
notes or the shares of common stock issuable upon conversion of the notes may be

                                      43



deemed to be "underwriters" within the meaning of the Securities Act, in which
event any commissions received by these broker-dealers, agents or underwriters
and any profits realized by the selling securityholders on the resales of the
notes or the shares may be deemed to be underwriting commissions or discounts
under the Securities Act.

     In addition, any securities covered by this prospectus which qualify for
sale pursuant to Rule 144, Rule 144A or any other available exemption from
registration under the Securities Act may be sold under Rule 144, Rule 144A or
any of the other available exemptions rather than pursuant to this prospectus.

     There is no assurance that any selling securityholder will sell any or all
of the notes or shares of common stock issuable upon conversion of the notes
described in this prospectus, and any selling securityholder may transfer,
devise or gift the securities by other means not described in this prospectus.

     AmeriSource originally sold the notes to the initial purchasers in December
2000 in a private placement. AmeriSource agreed to indemnify and hold the
initial purchasers of the notes harmless against certain liabilities under the
Securities Act that could arise in connection with the sale of the notes by the
initial purchasers. The registration rights agreement provides for AmeriSource
and the selling securityholders to indemnify each other against certain
liabilities arising under the Securities Act.

     AmeriSource agreed pursuant to the registration rights agreement to use
reasonable efforts to cause the registration statement to which this prospectus
relates to become effective within 180 days after the date the notes were
originally issued and to keep the registration statement effective until the
earlier of:

     .    the sale of all the securities registered under the registration
          rights agreement,

     .    the expiration of the holding period applicable to the securities
          under Rule 144(k) under the Securities Act with respect to persons who
          are not AmeriSource's affiliates, and

     .    two years from the date the notes were originally issued.

     The registration rights agreement provides that AmeriSource may suspend the
use of this prospectus in connection with sales of notes and shares of common
stock issuable upon conversion of the notes by holders for a period not to
exceed an aggregate of 45 days in any 90-day period or 90 days in any 12-month
period if any event occurs or any fact exists that would render the registration
statement materially misleading. AmerisourceBergen and AmeriSource will bear the
expenses of preparing and filing the registration statement and all post-
effective amendments.

                                 LEGAL MATTERS

     The validity of the notes and the shares of common stock issuable upon
conversion of the notes offered hereby will be passed upon for AmerisourceBergen
by Dechert, 4000 Bell Atlantic Tower, 1717 Arch Street, Philadelphia,
Pennsylvania 19103. Barton J. Winokur, a partner of Dechert, which performs
various legal services for the Company, is a director of AmeriSource and
beneficially owns 75,500 shares of its common stock.

                                     EXPERTS

     AmerisourceBergen Corporation. Ernst & Young LLP, independent auditors,
have audited the consolidated balance sheet of AmerisourceBergen Corporation as
of March 31, 2001, as set forth in their report which is incorporated by
reference in this prospectus and elsewhere in this registration statement.
AmerisourceBergen's consolidated balance sheet is incorporated by reference in
reliance on Ernst & Young LLP's report, given on their authority as experts in
accounting and auditing.

     AmerisourceBergen Corporation. The consolidated balance sheet of
AmerisourceBergen Corporation as of March 31, 2001, which is incorporated in
this prospectus by reference from Form S-4, has been audited by Deloitte &
Touche LLP, independent auditors, as stated in their report, which is
incorporated herein by reference, and has been so incorporated in reliance upon
the report of such firm given upon their authority as experts in accounting and
auditing.

     AmeriSource. Ernst & Young LLP, independent auditors, have audited the
consolidated financial statements and schedules of AmeriSource Health
Corporation included in AmeriSource's Annual Report on Form 10-K for the year
ended September 30, 2000, as set forth in their report, which is incorporated by
reference in this prospectus. AmeriSource's

                                       44



consolidated financial statements and schedules are incorporated by reference in
reliance on Ernst & Young LLP's report, given on their authority as experts in
accounting and auditing.

     Bergen. The consolidated financial statements and the related financial
statement schedules incorporated in this prospectus by reference from Bergen
Brunswig Corporation's Annual Report on Form 10-K for the year ended September
30, 2000 have been audited by Deloitte & Touche LLP, independent auditors, as
stated in their reports, which are incorporated herein by reference, and have
been so incorporated in reliance upon the reports of such firm given upon their
authority as experts in accounting and auditing.

                                       45




                                    PART II


                    INFORMATION NOT REQUIRED IN PROSPECTUS

Item 14. Other Expenses Of Issuance And Distribution.

         The following table sets forth an estimate of the expenses that will be
incurred by AmerisourceBergen in connection with the sale and distribution of
the common stock being registered in this registration statement.

              Securities and Exchange Commission registration fee...  $  0 (1)
              Printing and engraving expenses.......................    $25,000
              Legal fees and expenses...............................    $50,000
              Accounting fees and expenses..........................    $25,000
              Miscellaneous.........................................    $10.000
                                                                      ----------
              Total.................................................  $ 110,000
                                                                      ==========

(1) Previously paid pursuant to Rule 429 of the Securities Act.

Item 15. Indemnification of Directors and Officers.

         Delaware law provides that a corporation may include in its certificate
of incorporation a provision limiting or eliminating the liability of its
directors to the corporation and its stockholders for monetary damages arising
from a breach of fiduciary duty, except for:

         .        a breach of the duty of loyalty to the corporation or its
                  stockholders;

         .        acts or omissions not in good faith or which involve
                  intentional misconduct or a knowing violation of law;

         .        payment of a dividend or the repurchase or redemption of stock
                  in violation of Delaware law; or

         .        any transaction from which the director derived an improper
                  personal benefit.

         The amended and restated certificate of incorporation, as amended, of
AmerisourceBergen provides that the directors of AmerisourceBergen are entitled
to the benefits of all limitations on the liability of directors that are now or
hereafter become available under Delaware law. Specifically, no director of
AmerisourceBergen will be liable to AmerisourceBergen or its stockholders for
monetary damages for breach of fiduciary duty as director, except for liability
(a) for any breach of the director's duty of loyalty to AmerisourceBergen or its
stockholders, (b) for acts or omissions not in good faith or which involve
intentional misconduct or a knowing violation of law, (c) under section 174 of
the Delaware law, which pertains, among other things, to liability for the
unlawful payment of dividends, or (d) for any transaction from which the
director derived an improper personal benefit.

         Under Delaware law, a corporation may indemnify directors and officers:

         .        for actions taken in good faith and in a manner they
                  reasonably believed to be in, or not opposed to, the best
                  interests of the corporation; and

         .        with respect to any criminal proceeding, they had no
                  reasonable cause to believe that their conduct was unlawful.

         In addition, Delaware law provides that a corporation may advance to a
director or officer expenses incurred in defending any action upon receipt of an
undertaking by the director or officer to repay the amount advanced if it is
ultimately determined that he or she is not entitled to indemnification.


                                     II-1


         The amended and restated certificate of incorporation, as amended, of
AmerisourceBergen provides that AmerisourceBergen will indemnify any person who
is or was a director or officer of AmerisourceBergen, or is or was serving at
the request of AmerisourceBergen as a director, officer or trustee of another
corporation, trust or other enterprise, with respect to actions taken or omitted
by such person in any capacity in which such person serves AmerisourceBergen or
such other corporation, trust or other enterprise, to the full extent authorized
or permitted by law, as now or hereafter in effect, and such right to
indemnification will continue as to a person who has ceased to be a director,
officer or trustee, as the case may be, and will inure to the benefit of such
person's heirs, executors and personal and legal representatives.

Item 16. Exhibits.

         The following exhibits are filed herewith unless otherwise indicated:

Exhibit                                     Description
Number

3.1*            Amended and Restated Certificate of Incorporation, as amended,
                of AmerisourceBergen Corporation (incorporated by reference to
                Exhibit 3.1 to the Registration Statement on Form S-4 filed on
                May 23, 2001 (Registration No. 333-61440)).

3.2*            Amended and Restated Bylaws of AmerisourceBergen Corporation
                (incorporated by reference to Exhibit 3.2 to the Registration
                Statement on Form S-4 filed on May 23, 2001 (Registration No.
                333-61440)).

4.1*            Indenture, dated as of December 12, 2000, among AmeriSource
                Health Corporation, as Issuer, AmeriSource Corporation, as
                Guarantor, and Bank One Trust Company, N.A., as Trustee for the
                5% Convertible Subordinated Notes due December 15, 2007
                (incorporated by reference to Exhibit 4.16 to AmeriSource Health
                Corporation's Quarterly Report on Form 10-Q for the quarter
                ended December 31, 2000).

4.2*            Registration Rights Agreement, dated December 12, 2000, among
                AmeriSource Health Corporation, as Issuer, AmeriSource
                Corporation, as Guarantor, and the Purchasers for the 5%
                Convertible Subordinated Notes due December 15, 2007
                (incorporated by reference to Exhibit 4.18 to AmeriSource Health
                Corporation's Quarterly Report on Form 10-Q for the quarter
                ended December 31, 2000).

4.3*            Form of 5% Convertible Subordinated Note (included in Exhibit
                4.1).

4.4**           First Supplemental Indenture dated as of August __, 2001 among
                AmeriSource Health Corporation, as issuer, AmeriSource
                Corporation, as guarantor, AmerisourceBergen Corporation and
                Bank One Trust Company, N.A., as Trustee.

5.1**           Opinion of Dechert regarding legality of securities being
                registered.

12.1            Computation of Ratio of Earnings to Fixed Charges.

23.1**          Consent of Dechert (included as part of its opinion filed as
                Exhibit 5.1 and incorporated herein by reference).

23.2            Consent of Deloitte & Touche LLP Independent Auditors.

23.3            Consent of Ernst & Young LLP Independent Auditors.

24.1            Power of Attorney (included on the signature page of this Form
                S-3 and incorporated herein by reference).


                                     II-2


25.1*           Form T-1 Statement of Eligibility of Trustee for Indenture under
                the Trust Indenture Act of 1939 (incorporated by reference to
                Exhibit 25.1 to AmeriSource Health Corporation's Registration
                Statement on Form S-3 filed March 2, 2001).

-----------------
*        Previously filed.
**       To be filed by Amendment.


Item 17. Undertakings.

         Each undersigned Registrant hereby undertakes:

         (1)   To file, during any period in which offers or sales are being
made, a post-effective amendment to this Registration Statement:

               (a)  To include any prospectus required by Section 10(a)(3) of
the Securities Act of 1933,

               (b)  To reflect in the prospectus any facts or events arising
after the effective date of the registration statement (or the most recent post-
effective amendment thereof) which, individually or in the aggregate, represent
a fundamental change in the information set forth in the Registration Statement.

         Notwithstanding the foregoing, any increase or decrease in volume of
securities offered (if the total dollar value of securities offered would not
exceed that which was registered) and any deviation from the low or high end of
the estimated maximum offering range may be reflected in the form of prospectus
filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the
changes in volume and price represent no more than a 20 percent change in the
maximum aggregate offering price set forth in the "Calculation of Registration
Fee" table in the effective registration statement,

               (c)  To include any material information with respect to the plan
of distribution not previously disclosed in the Registration Statement or any
material change to such information in the Registration Statement; provided,
however, that clauses (a) and (b) do not apply if the information required to be
included in a post-effective amendment by such clauses is contained in periodic
reports filed with or furnished to the Securities and Exchange Commission by the
Registrant pursuant to Section 13 or Section 15(d) of the Securities Exchange
Act of 1934 (the "Exchange Act") that are incorporated by reference in the
Registration Statement.

          (2)  That, for the purpose of determining any liability under the
Securities Act, each such post-effective amendment shall be deemed a new
registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

          (3)  To remove from registration by means of a post-effective
amendment any of the securities being registered which remain unsold at the
termination of the offering.

          (4)  That, for purposes of determining any liability under the
Securities Act, each filing of the Registrant's annual report pursuant to
Section 13(a) or Section 15(d) of the Exchange Act that is incorporated by
reference in this Registration Statement shall be deemed to be a new
registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

          Insofar as indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers and controlling persons
of the Registrant pursuant to the provisions described under Item 15 above, or
otherwise, the Registrant has been advised that in the opinion of the Securities
and Exchange Commission such indemnification is against public policy as
expressed in the Securities Act and is, therefore, unenforceable. In the event
that a claim for indemnification against such liabilities, other than the
payment by the Registrant of expenses incurred or paid by a director, officer or
controlling person of the Registrant in the successful defense of any action,
suit or proceeding, is asserted by such director, officer or controlling person
in connection with the securities being registered, the Registrant will, unless
in the opinion of its counsel the matter has been settled by controlling
precedent, submit to a court of appropriate jurisdiction


                                     II-3


the question whether such indemnification by it is against public policy as
expressed in the Securities Act and will be governed by the final adjudication
of such issue.

         The undersigned registrant hereby undertakes to file an application for
the purpose of determining the eligibility of the trustee to act under
subsection (a) of Section 310 of the Trust Indenture Act in accordance with the
rules and regulations prescribed by the Commission under Section 305(b)(2) of
the Act.


                                     II-4


                                  SIGNATURES

         Pursuant to the requirements of the Securities Act, the Registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-3 and has duly caused this Registration
Statement on Form S-3 to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Chesterbrook, Commonwealth of Pennsylvania, on
August 24, 2001.

                                              AMERISOURCEBERGEN CORPORATION

                                              By: /s/ R. David Yost
                                              -------------------------------
                                                      R. David Yost
                                                      President and
                                                      Chief Executive Officer

         KNOW ALL MEN BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints William D. Sprague or R. David Yost as
his/her attorney-in-fact and agent, with full power of substitution and
resubstitution, for him/her and in his/her name, place, and stead, in any and
all capacities, to sign and file Registration Statement(s) and any and all pre-
or post-effective amendments to such Registration Statement(s), with all
exhibits thereto and hereto, and other documents with the Securities and
Exchange Commission, granting unto said attorney-in-fact and agent, and each of
them, full power and authority to do and perform each and every act and thing
requisite or necessary to be done in and about the premises, as fully to all
intents and purposes as he/she might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents, or any of them, or their
or his substitutes, may lawfully do or cause to be done by virtue hereof.

         Pursuant to the requirements of the Securities Act of 1933, as amended,
this prospectus has been signed by the following persons in the capacities and
on the dates indicated.


            Name                       Title                        Date

/s/ Robert E. Martini
---------------------
 Robert E. Martini    Chairman                                   August 24, 2001

/s/ R. David Yost
---------------------
 R. David Yost        President, Chief Executive Officer and     August 24, 2001
                      Director (Principal Executive Officer)


/s/ Kurt J. Hilzinger
---------------------
 Kurt J. Hilzinger    Executive Vice President, Chief Operating  August 24, 2001
                      Officer and Director


/s/ Neil F. Dimick
---------------------
 Neil F. Dimick       Executive Vice President, Chief Financial  August 24, 2001
                      Officer and Director (Principal Financial
                      Officer and Principal Accounting Officer)


          Pursuant to the requirements of the Securities Act, the Registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-3 and has duly caused this Registration
Statement on Form S-3 to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Chesterbrook, Commonwealth of Pennsylvania, on
August 24, 2001.

                                            AMERISOURCE HEALTH CORPORATION
                                            AMERISOURCE CORPORATION

                                            By: /s/ William D. Sprague
                                            ------------------------------------
                                                 William D. Sprague
                                                 Vice President, General Counsel
                                                 and Secretary



          KNOW ALL MEN BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints William D. Sprague or R. David Yost as
his/her attorney-in-fact and agent, with full power of substitution and
resubstitution, for him/her and in his/her name, place, and stead, in any and
all capacities, to sign and file Registration Statement(s) and any and all pre-
or post-effective amendments to such Registration Statement(s), with all
exhibits thereto and hereto, and other documents with the Securities and
Exchange Commission, granting unto said attorneys-in-fact and agent, and each of
them, full power and authority to do and perform each and every act and thing
requisite or necessary to be done in and about the premises, as fully to all
intents and purposes as he/she might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents, or any of them, or their
or his substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, as amended, this
prospectus has been signed by the following persons in the capacities and on the
dates indicated.



         Name                              Title                         Date
                                                                 
/s/ R. David Yost
------------------------
 R. David Yost             Chairman, Chief Executive Officer and       August 24, 2001
                           Director (Principal Executive Officer)
/s/ Lawrence C. Karlson
------------------------
 Lawrence C. Karlson       Vice Chairman and Lead Director             August 24, 2001

/s/ Bruce C. Bruckman
------------------------
 Bruce C. Bruckman         Director                                    August 24, 2001




                                                                
/s/ Richard C. Gozon
------------------------
 Richard C. Gozon          Director                                    August 24, 2001

/s/ George Strong
------------------------
 George Strong             Director                                    August 24, 2001

/s/ Edward Hagenlocker
------------------------
 Edward Hagenlocker        Director                                    August 24, 2001

/s/ J. Lawrence Wilson
------------------------
 J. Lawrence Wilson        Director                                    August 24, 2001

/s/ Barton J. Winokur
------------------------
 Barton J. Winokur         Director                                    August 24, 2001

/s/ George L. James, III
------------------------
 George L. James, III      Vice President and Chief Financial Officer  August 24, 2001
                           (Principal Financial Officer)
/s/ Michael D. DiCandilo
------------------------
 Michael D. DiCandilo      Vice President, Controller (Principal       August 24, 2001
                           Accounting Officer)