The present study reports the results of intravenous cyclosporine in 32 patients with refractory and/or severe attacks of ulcerative colitis (UC). Twenty of 32 patients responded to intravenous cyclosporine; cyclosporine was clinically effective and improved colonic lesions. However, one colonic perforation and one postoperative death were observed in two patients with severe endoscopic colitis who had failed to reach clinical remission with high-dose corticosteroids and cyclosporine. Moreover, after a median follow-up of 190 days, only one-third of the patients avoided colectomy. No predictive factor of response to cyclosporine was identified. This study confirms that cyclosporine is effective in severe UC but suggests that its use could be associated with serious complications in patients with severe lesions who had failed to settle with corticosteroids and cyclosporine.