Exhibit 12.1

McKESSON CORPORATION

COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES

	For the Nine Months Ended December 31, 2012			For the Years Ended March 31,
(Dollars in millions)				2012			2011			2010			2009			2008
Earnings:
Income from continuing operations before income taxes	$	1,533		$	1,919		$	1,635		$	1,864		$	1,064		$	1,457
Adjustments for equity in net income of and dividends from equity investees		(2	)		(2	)		9			(2	)		(1	)		(17	)
Fixed charges		230			332			280			240			195			198
Amortization of capitalized interest		2			3			3			4			4			4
Less: Capitalized interest		(1	)		(1	)		(3	)		—			(1	)		(3	)
Earnings as adjusted	$	1,762		$	2,251		$	1,924		$	2,106		$	1,261		$	1,639
Fixed charges:
Interest expense (a) (b)	$	170		$	251		$	222		$	187		$	144		$	142
Capitalized interest		1			1			3			—			1			3
Portion of rental expense representative of the interest factor (c)		59			80			55			53			50			53
Total fixed charges	$	230		$	332		$	280		$	240		$	195		$	198
Ratio:
Ratio of earnings to fixed charges		7.7			6.8			6.9			8.8			6.5			8.3

(a) Interest expense includes amortization of debt discounts and deferred loan costs.

(b) Interest accrued on the liability recorded for uncertain tax positions is excluded from interest expense.

(c) One-third of net rent expense is the portion of rental expense deemed representative of the interest factor.