Medical treatment of patients with ulcerative colitis (UC) presents a constant challenge. Corticosteroids are effective in the majority of patients, but benefits are offset by adverse events. For steroid-dependent patients therapeutic choices are limited to azathioprine/6-mercaptopurine, methotrexate and infliximab; however, 25% of more patients do not respond, become intolerant, or have contraindications (e.g. history of neoplasia) to these drugs.