EXHIBIT 24.2

POWER OF ATTORNEY

     Each of the undersigned does hereby appoint Celia A. Colbert and Kenneth C. Frazier, and each of them severally, to be his or her true and lawful attorney or attorneys to execute on behalf of the undersigned (whether on behalf of Merck & Co., Inc., or as an officer or director thereof, or by attesting the seal of the Company, or otherwise) a Registration Statement in connection with the registration under the Securities Act of 1933, as amended, of shares of Common Stock of Merck & Co., Inc. which may be purchased under the Merck & Co., Inc. 2007 Incentive Stock Plan (the “Plan”) covered by this Registration Statement, including amendments thereto and all other documents in connection therewith.

     IN WITNESS WHEREOF, this instrument has been duly executed as of the 19^th day of December 2006.

	MERCK & CO., INC.
By:	/s/ Richard T. Clark
	Richard T. Clark
	Chief Executive Officer and President
	(Principal Executive Officer; Director)
	/s/ Judy C. Lewent
	Judy C. Lewent
	Executive Vice President and Chief Financial Officer
	(Principal Financial Officer)
	/s/ John Canan
	John Canan
	Vice President, Controller
	(Principal Accounting Officer)

DIRECTORS

/s/ Lawrence A. Bossidy	/s/ Thomas E. Shenk
Lawrence A. Bossidy	Thomas E. Shenk
/s/ William G. Bowen	/s/ Anne M. Tatlock
William G. Bowen	Anne M. Tatlock
/s/ Johnnetta B. Cole	/s/ Samuel O. Thier
Johnnetta B. Cole	Samuel O. Thier
/s/ William B. Harrison, Jr.	/s/ Wendell P. Weeks
William B. Harrison, Jr.	Wendell P. Weeks
/s/ William N. Kelley	/s/ Peter C. Wendell
William N. Kelley	Peter C. Wendell
/s/ Rochelle B. Lazarus
Rochelle B. Lazarus

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