Ulcerative colitis is a chronic inflammatory bowel disease. The disease is diagnosed on the basis of clinical parameters and endoscopic-histologic evaluation. 5-aminosalicylic acid (5-ASA, mesalamine) represents the first-line treatment of choice. For patients with distal and left-sided disease the use of rectal preparations is effective. Most patients respond to 5-ASA suppositories or to topic steroids such as budesonide suppositories or hydrocortisone foam. For patients with extended disease, oral medications are mandatory. In case of low- to moderate-grade inflammation, 5-ASA preparations should be implemented. In the case of severe disease treatment with steroids is required. Following induction of remission, prophylactic treatment with 5-ASA (1.5 g/d) should be maintained. For patients with frequent or severe relapses, immunosuppressive therapy with azathioprine or 6-mercaptopurine is indicated. In case of a fulminant course of disease, treatment with intravenous cyclosporine is required in patients who have not responded to high-dose intravenous steroids. When all conservative treatment options fail, proctocolectomy with construction of an ileoanal pouch should be performed. New therapeutic strategies such as infliximab and interferons are being evaluated in clinical trials. The long-term complications of ulcerative colitis include steroid-induced osteoporosis and anemia and should be treated adequately. Finally, the risk for development of colorectal cancer increases steadily with disease duration and dysplasia should be screened for by endoscopic surveillance programs.