Celecoxib is a non-steroidal anti-inflammatory drug (NSAID) that is used to treat pain and inflammation associated with conditions such as arthritis, menstrual cramps, and acute pain. It works by blocking the production of certain substances in the body that cause pain and inflammation. Celecoxib is available in oral capsules and should be taken as directed by a healthcare provider. Common brand names for celecoxib include Celebrex and Onsenal.