Rofecoxib (IPA: ) is a nonsteroidal anti-inflammatory drug (NSAID) developed by Merck & Co. to treat osteoarthritis, acute pain conditions, and dysmenorrhoea.
Rofecoxib was approved as safe and effective by the Food and Drug Administration (FDA) on May 20, 1999 and was subsequently marketed under the brand name Vioxx, Ceoxx and Ceeoxx.

Rofecoxib gained widespread acceptance among physicians treating patients with arthritis and other conditions causing chronic or acute pain. Worldwide, over 80 million people were prescribed rofecoxib at some time.

On September 30, 2004, Merck voluntarily withdrew rofecoxib from the market because of concerns about increased risk of heart attack and stroke associated with long-term, high-dosage use. Rofecoxib was one of the most widely used drugs ever to be withdrawn from the market. In the year before withdrawal, Merck had sales revenue of US$2.5 billion from Vioxx.

Rofecoxib was available on prescription as tablets and as an oral suspension.