RULE 424(b)(3) 

                                                 SEC FILE NO: 333-26443 

  

                       STICKER SUPPLEMENT TO PROSPECTUS OF

                              MCKESSON CORPORATION

  

      The sole purpose of this Supplement dated September 30, 1998 is to

 replace the first two paragraphs set forth under the caption "Rights Plan"

 in the Prospectus dated June 18, 1997 (the "Prospectus") of McKesson

 Corporation.  This Supplement is part of, and must be read in conjunction

 with, the Prospectus.  Capitalized terms used in this Supplement have the

 meanings set forth in this Supplement or the Prospectus. 



      RIGHTS PLAN 

  

           Pursuant to the Company's Rights Agreement (as defined below),

      the Board declared a dividend distribution of one right (a "Right")

      for each outstanding share of Common Stock to stockholders of record

      of the Company at November 1, 1994 (the "Record Date").  As a result

      of the two-for-one stock split effective January 2, 1998, each share

      of Common Stock has attached to it one-half of a Right.  Each Right

      entitles the registered holder to purchase from the Company a unit

      consisting of one one-hundredth of a share of Series A Junior

      Participating Preferred Stock (the "Series A Preferred Stock") at a

      purchase price of $100 per unit.  The Rights expire on October 21,

      2004, unless redeemed earlier by the Board.  The terms of the Rights

      are set forth in a Rights Agreement between the Company and a Rights

      Agent (the "Rights Agreement"), a copy of which is filed with the

      Commission.  The following summary outlines certain provisions of the

      Rights Agreement and is qualified by reference to the full text of the

      Rights Agreement. 

  

           The Rights are attached to all Common Stock certificates

      representing shares outstanding at the Record Date and shares issued

      between the Record Date and the Distribution Date (as hereinafter

      defined), and no separate rights certificates (the "Rights

      Certificates") have been distributed.  The Rights will separate from

      the Common Stock, separate Rights Certificates will be issued and a

      distribution date (the "Distribution Date") will occur upon the

      earlier to occur of (i) ten business days following the date of a

      public announcement that there is an Acquiring Person (as defined

      below) (such date, the "Stock Acquisition Date"), (ii) ten business

      days (or such later date as the Board may determine) following

      commencement of a tender or exchange offer that would result in the

      offeror beneficially owning 15% or more of the Common Stock or (iii)

      ten business days after the Board determines that the ownership of 10%

      or more of the Company's outstanding Common Stock by a person is (A)

      intended to cause the Company to repurchase the Common Stock

      beneficially owned by such person or (B) is causing, or is reasonably

      likely to cause, a material adverse impact on the Company.