EXHIBIT 23 INDEPENDENT AUDITORS' CONSENT We consent to the incorporation by reference in McKesson Corporation Registration Statement Nos. 33-86536, 333-611, 333-2871, 333-21931, 333-32643, 333-32645, 333-43101, 333-43079, 333-48337, 333-48339, and 333-48859 on Form S-8 and Registration Statement Nos. 333-26443, and Amendment No. 1 thereto, and 333- 50985 on Form S-3, and Registration Statement No. 333-49119, and Amendment No. 1 thereto, on Form S-4 of our reports dated May 18, 1998 incorporated by reference in, and appearing in, this Annual Report on Form 10-K of McKesson Corporation, for the year ended March 31, 1998. DELOITTE & TOUCHE LLP San Francisco, California June 18, 1998 27