Despite intense investigative efforts, the causes of ulcerative colitis and Crohn's disease remain elusive. The mainstay of medical therapy focuses on inhibition of the effects of the inflammatory mediators operant in inflammatory bowel disease because the causes of these two chronic disorders are unknown. During recent years, the physician's armamentarium for medical treatment of inflammatory bowel disease has increased substantially. In this article, the current standard medical therapies available for treatment of patients with inflammatory bowel disease are reviewed along with their efficacy; the side effects and status of other investigative drugs also are reviewed.