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 that may be issued in connection with the assumption of stock option plans and employee stock purchase plans of HBO & Company in accordance with the terms of the Merger Agreement dated October 17, 1998 as amended November 9, 1998, among HBO & Company, McKesson Merger Sub, Inc. and McKesson Corporation, 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/ Mark A. Pulido ________________________ President, Chief Executive Officer and Mark A. Pulido Director (principal executive officer) /s/ Charles W. McCall ________________________ Chairman of the Board of Directors Charles W. McCall and Director /s/ Richard H. Hawkins ________________________ Senior Vice President and Chief Financial Richard H. Hawkins Officer (principal financial officer) /s/ Heidi E. Yodowitz ________________________ 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/ Gerald E. Mayo ________________________ Director Gerald E. Mayo /s/ James V. Napier ________________________ Director James V. Napier /s/ Carl E. Reichardt ________________________ Director Carl E. Reichardt /s/ Alan Seelenfreund ________________________ Director Alan Seelenfreund /s/ Jane E. Shaw ________________________ Director Jane E. Shaw Dated: January 12, 1999