Annual Meeting

The Annual Meeting of Stockholders will be held at 2 p.m., ET, on Tuesday, April 25, 2006, at the Edward Nash Theatre at Raritan Valley Community College, Route 28 and Lamington Road, North Branch, NJ.

Stock Trading Information

Merck stock is listed on the New York Stock Exchange (ticker symbol: MRK), the Philadelphia Stock Exchange and the Paris Stock Exchange.

Direct Purchase of Merck Stock and Dividend Reinvestment Plan

You can purchase shares directly from the Company through the Merck Stock Investment Plan. Shares also may be purchased by automatic investment each month. Merck's Dividend Reinvestment Plan allows dividends (all or part) to be automatically reinvested to purchase additional Merck shares. Call 800-522-9114, or write to:

Merck Stockholder Services, WS3AB-40
Merck & Co., Inc.
One Merck Drive, P.O. Box 100
Whitehouse Station, NJ 08889-0100

Stockholder Services

Call Monday through Friday, 8 a.m. to 8 p.m., ET, with questions on stock-related matters, including verification of your holdings, to change your address or to report lost or missing dividends. Call 800-522-9114, or write to Merck Stockholder Services at the address listed above.

For Changes or Lost Stock Certificates

If you want to transfer your stock, change ownership or if you have lost your stock certificates, call 800-522-9114, or write to:

Merck Shareowner Services
Wells Fargo Bank, N.A.
161 N. Concord Exchange
South St. Paul, MN 55075-1139

Independent Registered Public Accounting Firm

PricewaterhouseCoopers LLP
400 Campus Drive
Florham Park, NJ 07932
973-236-4000

News and Information

Merck offers the following services for individuals seeking business information about Merck:

• News on Call
  Anyone can access Merck news 24 hours a day, seven days a week. Included are the latest news releases on sales and earnings, dividends, new products and other Merck-related information. Call 800-CALL-MRK (800-225-5675).
• Investor Relations
  Securities analysts and investment professionals with business-related questions should call the Investor Relations department at 908-423-5881.
• Media Relations
  Professional journalists should visit www.merck.com/newsroom/ for information and a list of contacts.
• Copies of Corporate Documents
  For a copy of one of the following,
  visit www.merck.com or write to:

  Merck Public Affairs, WS1A-40
  Merck & Co., Inc.
  One Merck Drive, P.O. Box 100
  Whitehouse Station, NJ 08889-0100

  • Merck's 2005 Form 10-K Annual Report, as filed with the Securities and Exchange Commission;
  • Report on Diversity at Merck;
  • Policies of the Board — a statement of Merck governance principles;
  • Merck Board Committee Charters — Audit, Compensation and Benefits, and Committee on Corporate Governance;
  • Merck Code of Conduct — Our Values and Standards.

Trademarks

All product or service marks appearing in type form different from that of the surrounding text are trademarks or service marks owned by or licensed to Merck & Co., Inc., its subsidiaries or affiliates. Cozaar and Hyzaar are registered trademarks of E.I. du Pont de Nemours and Company, Wilmington, Delaware, USA. Zetia and Vytorin are trademarks owned by an entity of the Merck/Schering-Plough Pharmaceuticals partnership. Claritin is a trademark of Schering Corporation. Prilosec and Nexium are trademarks of the AstraZeneca group. The U.S. trademark for Vasotec is owned by Biovail Laboratories Incorporated. The U.S. trademark for Aggrastat is owned by Guilford Pharmaceuticals Inc.

Merck is a global, research-driven pharmaceutical company dedicated to putting patients first.

Merck offers several programs to give individuals greater access to the medicines they need:

• Information on the Merck Patient Assistance Program can be found at www.merckhelps.com or by calling 800-727-5400.
• The Merck Prescription Discount Program offers patients savings on many Merck medicines, regardless of age or income. More information is available at www.merckhelps.com or by calling 800-50-MERCK.
• NEW Merck's Guide to Affordable Medicine provides information for consumers on how to navigate the various government and private programs that offer medicines at a discount or for free. To receive a free copy, call 888-MERCK-38 or visit www.merckhelps.com.

Merck provides accurate, unbiased, convenient health care information free online, including:

• The Merck Manual — Second Home Edition, an easy-to-understand reference on general health issues, is available at www.merck.com.
• MerckSource.com is a broad-based medical Web site that provides patients with information to help them partner with their doctors.
• NEW Your Health Now is a health magazine powered by information and insights from The Merck Manuals, the world's most widely used medical reference books. Your Health Now is available free online at www.YourHealthNow.com.

Merck's 2004-05 Corporate Responsibility Report is now available online. More information about corporate responsibility at Merck is available at www.merck.com/cr.