On hospital days 1-2, hospitalized patients with severe ulcerative colitis undergo diagnostic evaluation including bloodwork (complete blood count, C-reactive protein, erythrocyte sedimentation rate, and serum albumin), infectious work-up (Clostridium difficile, stool cultures, stool ova and parasites, cytomegalovirus), and standardized assessment of disease activity (flexible sigmoidoscopy and calculation of UCDAI score). Patients are started on corticosteroid therapy (Solumedrol 40mg intravenous daily), and screened for eligibility for anti-tumor necrosis factor therapy (hepatitis B surface antibody, hepatitis B core antibody, hepatitis B surface antigen, tuberculin skin test, Quantiferon gold test, and chest radiograph). The Quantiferon gold tests are ordered for inpatients. Intravenous antibiotics are given therapeutically in the event of documented infection or clinical toxicity, but not prophylactically administered. Subcutaneous heparin is administered for deep vein thrombosis prophylaxis per standard of care. On hospital day 3, a positive or negative response to intravenous corticosteroids is determined prior to initiation of high-dose infliximab. Responders to medical therapy continue with an infliximab induction regimen (week 0, 2, and 6 infusions). After completing the induction regimen, patients undergo repeat flexible sigmoidoscopy and calculation of UCDAI score at week 8.