Merck & Co., Inc., Whitehouse Station, New Jersey, U.S.A., which operates in many countries as Merck Sharp & Dohme (MSD), is a global research-driven pharmaceutical company that discovers, develops, manufactures and markets a broad range of human health products.

Human health products include therapeutic and preventive agents, generally sold by prescription, for the treatment of human disorders. These products fall under the therapeutic categories of cardiovascular and hypertensive, endocrinology, gastrointestinal, infection, inflammation, neurological, ophthalmic, respiratory and vaccines.

Merck's pharmacy benefit management also represents an important part of Merck's business. In the United States, Merck-Medco Managed Care manages pharmacy benefits for employers, insurers and other plan sponsors, encouraging the appropriate use of medicines and providing disease management programs.