Crohn's disease is a lifelong illness characterized by chronic recurrent flares. The precise etiology of Crohn's disease is unknown. However, it appears to involve an enhanced systemic immune response and intensified local intestinal mucosal inflammatory activity, mediated through various inflammatory cells and an array of proinflammatory cytokines. Corticosteroids have been the mainstay of treatment of Crohn's disease. The controlled trials of the National Cooperative Crohn's Disease Study and the European Cooperative Crohn's Disease Study established that corticosteroids were effective for the induction of remission in Crohn's disease for the duration of the studies (6-17 wk). However, corticosteroids have not been shown to have an impact on the maintenance of long term remission in patients with Crohn's disease. In addition, they are associated with a high potential for dependence and serious toxic side effects. Alternative classes of medical therapy for Crohn's disease, including modified corticosteroids and a group of new biological therapies, have proven to be efficacious in the management of active and/or quiescent Crohn's disease.