EXHIBIT 8.2
                    
                 SKADDEN, ARPS, SLATE, MEAGHER & FLOM LLP     
                                
                             919 THIRD AVENUE     
                          
                       NEW YORK, NEW YORK 10022-3897     
                               
                            TEL: (212) 735-3000     
                               
                            FAX: (212) 735-2000     
                                             
                                          November 27, 1998     
 
McKesson Corporation
McKesson Plaza
One Post Street
San Francisco, California 94104
 
Dear Sir or Madam:
 
  You have requested our opinion, as counsel to McKesson Corporation, a
Delaware corporation ("McKesson"), as to certain United States federal income
tax consequences of the proposed merger of McKesson Merger Sub, Inc., a
Delaware corporation ("Merger Sub"), and a wholly owned subsidiary of McKesson,
with and into HBO & Company ("HBOC"), with HBOC continuing as the surviving
corporation.
 
  In rendering our opinion, we have reviewed the Agreement and Plan of Merger,
dated as of October 17, 1998, as amended as of November 9, 1998, among
McKesson, Merger Sub and HBOC (the "Merger Agreement") and such other materials
as we have deemed necessary or appropriate as a basis for our opinion.
Capitalized terms not otherwise defined herein have the meaning specified in
the Merger Agreement. All section references, unless otherwise indicated, are
to the Internal Revenue Code of 1986, as amended (the "Code").
 
  In rendering this opinion, we have assumed that the Merger will be
consummated in accordance with the Merger Agreement. In addition, as to certain
facts material to our opinion, we have relied upon the accuracy of written
representations made by an authorized officer of each of McKesson, Merger Sub,
and HBOC in letters addressed to us and Jones, Day, Reavis & Pogue (the "Tax
Representation Letters"), copies of which are attached hereto. Our opinion is
conditioned on, among other things, the accuracy and completeness as of the
date hereof, of such facts, information, covenants and representations referred
to above. We note that while we have not undertaken any independent
investigation, nothing has come to our attention during the course of our
representation of McKesson that is inconsistent with these facts, information,
covenants and representations.
 
  In our examination of documents in connection with this opinion, we have
assumed the genuineness of all signatures, the legal capacity of natural
persons, the authenticity of all documents submitted to us as originals, the
conformity to original documents of all documents submitted to us as certified
or photostatic copies and the authenticity of the originals of such documents.
 
  Based on our examination of the foregoing items and subject to the
limitations, qualifications, assumptions and caveats set forth herein, we are
of the opinion that, assuming that the Merger is consummated in accordance with
the Merger Agreement (and without any waiver, breach or

 
   
November 27, 1998     
Page 2
 
amendment of any of the provisions thereof) and the statements set forth in the
Tax Representation Letters are true and correct as of the Effective Time, then
for federal income tax purposes, the Merger will constitute a reorganization
within the meaning of Section 368 of the Code.
 
  This opinion does not address the various state, local or foreign tax
consequences that may result from the Merger or the other transactions
contemplated by the Merger Agreement. In addition, no opinion is expressed as
to any federal income tax consequence of the Merger or the other transactions
contemplated by the Merger Agreement except as specifically set forth herein,
and this opinion may not be relied upon except with respect to the consequences
specifically discussed herein. To the extent that any of the representations,
warranties, statements and assumptions material to our opinion and upon which
we have relied are not accurate and complete in all material respects at all
relevant times, our opinion would be adversely affected and should not be
relied upon.
 
  This opinion only represents our best judgment as to the federal income tax
consequences of the Merger and is not binding on the Internal Revenue Service
or any court of law, tribunal, administrative agency or other governmental
body. The conclusions are based on the Code, existing judicial decisions,
administrative regulations and published rulings. No assurance can be given
that future legislative, judicial or administrative changes or interpretations
would not adversely affect the accuracy of the conclusions stated herein.
Nevertheless, by rendering this opinion, we undertake no responsibility to
advise you of any new developments in the application or interpretation of the
federal income tax laws.
 
  This opinion is being delivered to you for the purpose of being included as
an exhibit to the Registration Statement, and is intended for the benefit of
McKesson and its shareholders and may not be relied upon or utilized for any
other purpose or by any other person and may not be made available to any other
person without our prior written consent.
 
  We hereby consent to the filing of this opinion as an exhibit to the
aforementioned Registration Statement and to references to Skadden, Arps,
Slate, Meagher & Flom LLP and its opinion in the sections captioned "Certain
United States Federal Income Tax Consequences of the Merger" and "Legal
Matters" in the Registration Statement and Joint Proxy Statement/Prospectus. In
giving this consent, we do not admit that we come within the category of
persons whose consent is required under Section 7 of the Securities Act of
1933, as amended, or the rules and regulations of the Securities and Exchange
Commission thereunder.
 
                                   Very truly yours,
                                      
                                   /s/ Skadden, Arps, Slate, Meagher & Flom
                                    LLP