Megacolon is a serious complication of inflammatory bowel disease that often requires a colectomy. Infliximab is a therapeutic alternative when conventional treatment fails, before resorting to surgery. Its use is currently based on the publication of isolated cases. We present a series of 12 patients with megacolon treated with infliximab, five with signs of systemic toxicity. Seventy-five percent of the patients avoided a colectomy during their acute episode after early infliximab treatment, 2.45 days after the megacolon diagnosis. There was a greater risk of surgery among patients with ulcerative colitis and toxicity criteria. Two more patients required follow-up surgery despite long-term infliximab treatment. No patient suffered significant treatment-related adverse effects or significant post-surgery complications.