Severe flares, or fulminant ulcerative colitis, remain highly morbid and potentially fatal presentations of disease. Traditionally, hospitalized patients who failed high-dose intravenous corticosteroid therapy require life-saving colectomy. Although the advent of infliximab has presented an alternative rescue therapy, some patients with severe ulcerative colitis are non-responders to anti-TNF induction therapy and proceed to colectomy. In the ACT I and II trials, outpatients with moderate to severe ulcerative colitis were randomized to placebo, 5mg/kg infliximab therapy, or 10mg/kg infliximab therapy. At 54 week follow-up, patients receiving infliximab had a 41% reduced risk of colectomy compared to the placebo group. Although infliximab at 5mg/kg was associated with a reduced risk of colectomy, only the 10mg/kg infliximab dosing yielded a statistically significant risk reduction. There were no differences in safety between the 5mg/kg and 10mg/kg infliximab groups; similar rates of serious adverse events, infections, and infusion reactions were reported. Thus, at our institution (University of California at San Francisco), it is our standard of care to administer infliximab at 10mg/kg IV for patients hospitalized with severe ulcerative colitis.