In around 30-40% of patients with acute severe ulcerative colitis the disease is refractory to treatment with high-dose glucocorticoids. Adding intravenous cyclosporine to the therapy in these patients has shown encouraging short-term results. Case notes of twenty-three acutely ill patients, who received intravenous cyclosporine during the period 1992 to 1998 due to failure of high-dose glucocorticoid (n = 20) or due to medical complications (n = 3) which made surgery difficult, were reviewed. Eight patients had their first episode of ulcerative colitis whereas 15 had relapse or chronic active disease. Cyclosporine (4 mg/kg/dag) was added to glucocorticoid treatment after a median of 11 days. Clinical remission was achieved in 13 patients (57%) after a median of nine days, of these five subsequently underwent surgery. Ten did not obtain remission and went to surgery. Approximately a third of acutely ill ulcerative colitis patients refractory to standard treatment with high-dose glucocorticoids will benefit from intravenous cyclosporine in the longer term.