Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in Registration Statement Nos. 033-86536, 333-50261, and 333-84806 on Form S-8 of our report dated September 21, 2010 relating to the financial statements and financial statement schedule of McKesson Corporation Profit-Sharing Investment Plan appearing in this Annual Report on Form 11-K of the McKesson Corporation Profit-Sharing Investment Plan for the year ended March 31, 2010.

/s/ Deloitte & Touche LLP
San Francisco, CA
September 21, 2010