Exhibit 24.1 POWER OF ATTORNEY KNOW ALL MEN BY THESE PRESENTS THAT the undersigned directors and officers of McKesson HBOC, Inc., a Delaware corporation (the "Company"), do hereby constitute and appoint Ivan D. Meyerson and Nancy A. Miller his or her true and lawful attorney and agent, each with full power and authority (acting alone and without the other) to execute in the name and on behalf of the undersigned as such Director and/or officer, a Registration Statement on Form S- 8 under the Securities Act of 1933, as amended, with respect to the registration of shares of the Company's Common Stock, par value $.01 per share, that may be issued by the Company in connection with the McKesson HBOC, Inc. 1999 Executive Stock Purchase Plan, and to execute any and all amendments to such Registration Statement, whether filed prior or subsequent to the time such Registration Statement becomes effective. The undersigned hereby grants unto such attorneys and agents, and each of them, full power of substitution and revocation in the premises and hereby ratifies and confirms all that such attorneys and agents may do or cause to be done by virtue of these presents. Signature Title - --------- ----- /s/ Charles W. McCall - -------------------------- Chairman of the Board of Directors and Director Charles W. McCall /s/ Mark A. Pulido - -------------------------- President, Chief Executive Officer and Director Mark A. Pulido (principal executive officer) /s/ Richard H. Hawkins - -------------------------- Executive Vice President and Chief Financial Richard H. Hawkins Officer (principal financial officer) /s/ Heidi E. Yodowitz - -------------------------- Senior Vice President and Controller Heidi E. Yodowitz (principal accounting officer) /s/ Alfred C. Eckert III - -------------------------- Director Alfred C. Eckert III /s/ Tully M. Friedman - -------------------------- Director Tully M. Friedman /s/ Alton F. Irby III - -------------------------- Director Alton F. Irby III /s/ M. Christine Jacobs - -------------------------- Director M. Christine Jacobs /s/ Gerald E. Mayo - -------------------------- Director Gerald E. Mayo /s/ James V. Napier - -------------------------- Director James V. Napier /s/ David S. Pottruck - -------------------------- Director David S. Pottruck /s/ Carl E. Reichardt - -------------------------- Director Carl E. Reichardt /s/ Alan Seelenfreund - -------------------------- Director Alan Seelenfreund /s/ Jane E. Shaw - -------------------------- Director Jane E. Shaw Dated: February 5, 1999