EXHIBIT 24.2

POWER OF ATTORNEY

Each of the undersigned directors and each of the undersigned officers of
McKesson HBOC, Inc., a Delaware corporation (the "Corporation"), does hereby
constitute and appoint Ivan D. Meyerson and Kristina Veaco as his or her true
and lawful attorney-in-fact and agent, each with full power of substitution and
resubstitution (acting alone and without the other), for him or her and in his
or her name, place and stead in any and all capacities, to execute and deliver
in his or her name and on his or her behalf any and all post-effective
amendments to the Registration Statement on Form S-3 (Registration No. 333-
66359) under the Securities Act of 1933, as amended (the "Securities Act"), with
respect to the deregistration of common stock of the Corporation registered
thereunder (the "Common Stock"), and to file the same with all exhibits thereto
and any other documents in connection therewith and any and all other
certificates, letters, reports, statements, applications and any other documents
and instruments in connection with the deregistration of the Common Stock which
such attorney-in-fact and agent deems necessary, advisable or appropriate to
enable the Corporation to comply with (i) the Securities Act, the Securities
Exchange Act of 1934, as amended, and the other federal securities laws of the
United States of America and the rules, regulations and requirements of the
Securities and Exchange Commission in respect of any thereof; (ii) the
securities or Blue Sky laws of any state or other governmental subdivision of
the United States of America; and (iii) the securities or similar applicable
laws of any foreign jurisdiction, and each of the undersigned hereby grants unto
such attorney-in-fact and agent or his substitute or substitutes, each and every
act and thing requisite and necessary to be done in and about the premises as
fully as to all intents and purposes as he or she might or could do in person,
and does hereby ratify and confirm as his or her own acts and deeds all that
such attorney-in-fact and agent, or his substitute or substitutes, shall
lawfully do or cause to be done by virtue hereof. Such attorney-in-fact and
agent shall have, and may exercise, all of the powers hereby conferred.

IN WITNESS WHEREOF, the undersigned has hereunto subscribed this power of
attorney this 27th day of April, 1999.

/s/ Charles W. McCall /s/ Alfred C. Eckert III
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Charles W. McCall Alfred C. Eckert III

/s/ Tully M. Friedman /s/ James V. Napier
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Tully M. Friedman James V. Napier

/s/ Alton F. Irby III /s/ David S. Pottruck
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Alton F. Irby III David S. Pottruck

/s/ M. Christine Jacobs /s/ Carl E. Reichardt
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M. Christine Jacobs Carl E. Reichardt

/s/ Gerald E. Mayo
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Gerald E. Mayo