Rofecoxib is a COX-2-selective nonsteroidal anti-inflammatory drug (NSAID). It was marketed by Merck & Co. to treat osteoarthritis, rheumatoid arthritis, juvenile rheumatoid arthritis, acute pain conditions, migraine, and dysmenorrhea. Rofecoxib was approved in the US by the US Food and Drug Administration (FDA) in May 1999, and was marketed under the brand names Vioxx, Ceoxx, and Ceeoxx. Rofecoxib was available by prescription in both tablets and as an oral suspension.

Merck & Co., Inc. is an American multinational pharmaceutical company headquartered in Rahway, New Jersey, and is named for Merck Group, founded in Germany in 1668, of which it was once the American arm. The company does business as Merck Sharp & Dohme or MSD outside the United States and Canada. It is one of the largest pharmaceutical companies in the world, generally ranking in the global top five by revenue.