Rofecoxib, a selective non-steroidal anti-inflammatory drug (NSAID), inhibits COX-2 over COX-1 with IC50 values of 0.018 and >15 µM, respectively, for PGE2 production. In vivo, it suppresses carrageenan-induced paw edema and hyperalgesia (ID50s = 1.5 and 1.0 mg/kg), LPS-induced pyresis (ID50 = 0.24 mg/kg/day), and M. butyricum-induced arthritis (ID50 = 0.74 mg/kg/day) in rats. Previously, rofecoxib formulations were employed in pain and arthritis treatment.