From January 1983 to December 1988, 88 consecutive patients with ambulatory ischemic colitis without severe disease or surgical operation were observed. The diagnosis was established in all cases by endoscopy, and in 64 cases by histologic examination. The study included 55 women and 33 men with a mean age of 65.4 years (22-90). Symptoms included: abdominal pain (73 percent), diarrhea (60 percent) and bloody stools (85 percent). The sequence abdominal pain-diarrhea-bloody stools was noted in 41 percent of cases. Most cases of colitis were located in the sigmoid and left colon. The immediate course was uneventful in 81 patients. Six patients underwent surgery and of these, three died. The mortality rate was 4.5 percent (4 cases). Long-term outcome was known in 41 cases. None of the patients were symptomatic, but a moderate secondary stenosis was noted in 4 of 31 patients who underwent endoscopic or radiological follow-up examination. In 80 cases, one or more potentially etiological factors were observed including vascular obstruction (32 cases), low-flow states (27 cases), and drugs (78 cases). Twenty patients were taking non steroidal anti-inflammatory drugs (23 percent). Drug treatment was recent in 10 cases, and in four, it was the only possible etiological factor. This suggests the responsibility of anti-inflammatory drugs in the onset of certain cases of ischemic colitis.