The use of cyclosporine in refractory ulcerative colitis (UC) is still controversial. An 8-year-long retrospective review open-label treatment with intravenous cyclosporine in 21 patients with steroid-refractory UC is therefore in order. Intravenous cyclosporine, 5 mg/kg-1 day, was added to ongoing drug therapy. Those who responded were switched to oral cyclosporine for a mean 8.4-month period, and steroids were discontinued when possible. Sixteen out of 21 patients improved (76%). Mean latency time to onset of improvement was 9 days. Five did not improve: three underwent urgent surgery, one was switched to methotrexate, and the remainder died. While on oral cyclosporine, 10 out of 16 maintained remission and seven could discontinue steroids, five relapsed, and one went on continuous mild activity. One patient died of a Pneumocystis carinii pneumonia, while in remission. Five reversible episodes of hepatobiliary toxicity were recorded. Intravenous cyclosporine effectively and rapidly induces improvement of acute steroid-refractory flare-ups of UC and helps to prevent urgent surgery. However, major adverse events may limit its usefulness.