<PAGE>
 
 
 
 
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
 
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
 
                               ----------------
 
                                 SCHEDULE 14D-1
 
              TENDER OFFER STATEMENT PURSUANT TO SECTION 14(D)(1)
                     OF THE SECURITIES EXCHANGE ACT OF 1934
 
                               (AMENDMENT NO. 2)
 
                               ----------------
 
                              MCKESSON CORPORATION
                           (NAME OF SUBJECT COMPANY)
 
                          ECO ACQUISITION CORPORATION
                          A WHOLLY OWNED SUBSIDIARY OF
                             ELI LILLY AND COMPANY
                                   (BIDDERS)
 
COMMON STOCK, $2.00 PAR VALUE PER SHARE               581556 10 7
   (INCLUDING THE ASSOCIATED RIGHTS)     (CUSIP NUMBER OF CLASS OF SECURITIES)
     (TITLE OF CLASS OF SECURITIES)
 
                                J.B. KING, ESQ.
                       VICE PRESIDENT AND GENERAL COUNSEL
                             ELI LILLY AND COMPANY
                             LILLY CORPORATE CENTER
                          INDIANAPOLIS, INDIANA 46285
                                 (317) 276-2000
         (NAMES, ADDRESSES AND TELEPHONE NUMBERS OF PERSONS AUTHORIZED
           TO RECEIVE NOTICES AND COMMUNICATIONS ON BEHALF OF BIDDER)
 
                                WITH A COPY TO:
 
                             BERNARD E. KURY, ESQ.
                                DEWEY BALLANTINE
                          1301 AVENUE OF THE AMERICAS
                            NEW YORK, NEW YORK 10019
                                 (212) 259-7400
 
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------

<PAGE>
 
  This Amendment No. 2 to the Schedule 14D-1 relates to a tender offer by ECO
Acquisition Corporation (the "Purchaser"), a Delaware corporation and a wholly
owned subsidiary of Eli Lilly and Company, an Indiana corporation ("Parent"),
to purchase all outstanding shares of common stock, par value $2.00 per share
and the associated Rights (as defined in the Offer to Purchase) (collectively,
the "Shares"), of McKesson Corporation (the "Company"), a Delaware corporation,
at a purchase price of $76.00 per Share, net to the seller in cash, without
interest, upon the terms and subject to the conditions set forth in the Offer
to Purchase, dated July 15, 1994 (the "Offer to Purchase"), and the related
Letter of Transmittal (which together constitute the "Offer"), copies of which
were attached as Exhibits (a)(1) and (a)(2), respectively, to the Schedule 14D-
1 filed with the Securities and Exchange Commission on July 15, 1994 as amended
by Amendment No. 1 thereto dated July 27, 1994 (collectively, the "Schedule
14D-1"). The purpose of this Amendment No. 2 is to amend and supplement Item 11
of the Schedule 14D-1 as described below.
 
ITEM 11. MATERIAL TO BE FILED AS EXHIBITS.
 
  (a)(18)   --Amendment, dated as of August 8, 1994, by and among the Company,
             Parent and the Purchaser.
 
  (a)(19)   --Form of press release issued by Parent on August 10, 1994.
 
 
                                       1

<PAGE>
 
                                   SIGNATURE
 
  AFTER DUE INQUIRY AND TO THE BEST OF ITS KNOWLEDGE AND BELIEF, EACH OF THE
UNDERSIGNED CERTIFIES THAT THE INFORMATION SET FORTH IN THIS STATEMENT IS TRUE,
COMPLETE AND CORRECT.
 
                                          Eli Lilly and Company
 
                                              
                                          By:     /s/ James M. Cornelius
                                              ---------------------------------
                                              Name:  James M. Cornelius
                                              Title: Vice President, Finance and
                                                     Chief Financial Officer
 
                                          ECO Acquisition Corporation
 
                                              
                                          By:    /s/ Charles E. Schalliol
                                              ---------------------------------
                                              Name:  Charles E. Schalliol
                                              Title: President
 
Dated: August 10, 1994
 
                                       2





<PAGE>
 
                                                                 EXHIBIT (A)(18)
 
                                   AMENDMENT
 
  AMENDMENT, dated as of August 8, 1994 (the "Amendment"), by and among
McKesson Corporation, a Delaware corporation (the "Company"), Eli Lilly and
Company, an Indiana corporation ("Parent"), and ECO Acquisition Corporation, a
Delaware corporation and a wholly-owned subsidiary of Parent (the "Purchaser").
 
  WHEREAS, the Company, Parent and the Purchaser entered into an Agreement and
Plan of Merger, dated as of July 10, 1994 (the "Merger Agreement"); and
 
  WHEREAS, each of the parties hereto have deemed it advisable to amend the
Merger Agreement in the manner set forth herein.
 
  NOW, THEREFORE, in consideration of the foregoing, the parties hereto hereby
agree as follows:
 
    1. Section 2.10(a)(i) of the Merger Agreement is hereby amended by adding
  to the end of such Section the following proviso:
 
    "; provided that each such employee, former employee, director or
    former director shall have the right to elect to defer (the "Deferral
    Election") the receipt of all or any portion of such cash amount (any
    such deferred amount, the "Deferred Option Amount"), on such terms and
    conditions as may be provided prior to the Effective Time by the
    Company and Spinco (with respect to Spinco Employees (as defined in the
    Distribution Agreement) and
 non-employee directors of the Company) or
    by Parent (with respect to Retained Employees (as defined in Section
    6.9 hereof)). In the event of any Deferral Election which is agreed
    upon by the Company and Spinco, Spinco shall be solely liable for the
    payment of the Deferred Option Amount with respect thereto and the
    Company shall not be obligated to make any payments at the Effective
    Time or at any other time with respect to such Deferred Option amount."
 
    2. Section 2.13(b)(ii) of the Merger Agreement is hereby amended to read,
  in its entirety, as follows:
 
    "(ii) the amount paid or payable with respect to Section 2.10(a)(i)
    hereof (excluding the aggregate amount of all Deferred Option Amounts
    with respect to which Spinco has become liable pursuant to such Section
    2.10(a)(i)) and"
 
    3. In the event of a conflict between the terms and conditions of this
  Amendment and the terms and conditions of the Merger Agreement, the terms
  and conditions of this Amendment shall prevail and govern. Except as
  otherwise expressly set forth herein, the Merger Agreement shall remain
  unaffected and in full force and effect in accordance with the terms and
  conditions thereof.
 
    4. This Amendment may be executed in two or more counterparts, each of
  which shall be deemed an original, but all of which together shall
  constitute one and the same instrument.
 
    5. This Amendment shall be governed by and construed in accordance with
  the laws of the State of Delaware, regardless of the laws that might
  otherwise govern under applicable principles of conflicts of law.

<PAGE>
 
  IN WITNESS WHEREOF, each of the parties set forth below has caused this
Amendment to be executed on its behalf by a duly authorized officer as of the
date first set forth above.
 
                                          MCKESSON CORPORATION
 
                                                  /s/ Garret A. Scholz
                                          By:____________________________ 
                                             Name: Garret A. Scholz
                                             Title: Vice President Finance
 
                                          ELI LILLY AND COMPANY
 
                                                  /s/ Randall L. Tobias
                                          By:____________________________
                                             Name: Randall L. Tobias
                                             Title: Chairman and Chief
                                             Executive Officer
 
                                          ECO ACQUISITION CORPORATION
 
                                                /s/ Charles E. Schalliol
                                          By:___________________________
                                             Name: Charles E. Schalliol
                                             Title: President
 
 
                                       2



<PAGE>
 
                                                                EXHIBIT (A )(19)
 
                                          August 10, 1994
                                          Immediately
                                          (317) 276-3655
 
                      LILLY EXTENDS MCKESSON TENDER OFFER
 
  Eli Lilly and Company (NYSE:LLY) announced today that it is extending its
offer to purchase all outstanding shares of common stock of McKesson
Corporation for $76.00 per share in cash until 5:00 p.m, New York City time, on
Friday, September 9, 1994.
 
  The terms of the extended offer are identical to the terms of the original
offer announced on July 11,1994. Therefore, in addition to the $76.00 per share
in cash, when the transaction is completed, McKesson Corporation will
distribute to its stockholders one share of common stock in a newly formed
McKesson corporation for each share in the old McKesson Corporation.
 
  As previously announced, a request for additional information was made by the
Federal Trade Commission (FTC) pursuant to the Hart-Scott-Rodino Antitrust
Improvements Act in connection with Lilly's acquisition of McKesson's PCS
Health Systems, Inc., business. The offer is being extended to provide time for
Lilly and McKesson to comply with the FTC's request and to permit McKesson to
transfer all its non-PCS assets and liabilities to a newly formed corporation
and distribute the common stock of the new corporation
 to McKesson
stockholders. For these reasons, it may be necessary to further extend the
offer.
 
  As of Tuesday, August 9, 1994 approximately 6,738,800 shares of McKesson
common stock had been tendered.
 
                                     * * *