Ulcerative colitis is characterized by chronic inflammation of the colon. Typical symptoms are diarrhoea, rectal bleeding, abdominal pain and fever. The aetiology of the disease is unclear. The inflammation can be localized in the rectum or can extend to the left side or the whole colon. Treatment for induction and remission maintenance depends on the severity and extension of mucosal inflammation. Topical 5-aminosalicylates have been shown in studies to be the treatment of choice in mild to moderate ulcerative colitis. Oral 5-aminosalicylates can be used in distal, mild and moderate ulcerative colitis and for remission maintenance. For patients with a more extended or severe inflammation, oral or i.v. corticosteroids should be used. Patients with severe and/or chronic disease require immunosuppressive therapy with azathioprine or 6-mercaptopurine. For patients with severe, chronic, refractory disease, cyclosporine i.v. can be used. If no response to treatment is seen, proctocolectomy should be considered. Biological agents such as beta-Interferon seem to be effective in mild to moderately ulcerative colitis, but further studies have to be performed.