Ischemic colitis is not well characterized in the young adult population, despite its commonness in older patients. The aim of this study was to investigate the demographics, etiology, clinical features, and prognosis of ischemic colitis in young adults. We conducted a retrospective study of 39 young adults (<50 years of age) diagnosed with ischemic colitis over a period of 9 years (1990 to 1998). The mean age at diagnosis was 38 +/- 2 years (range 18 to 49 years); the female:male ratio was 1.8. Fifty-two percent (13 of 25) of women were using oral contraceptives at the time of diagnosis. Other potential associations identified were vascular thromboembolism (4 of 39), vasoactive drugs (4 of 39), hypovolemia (4 of 39), and vasculitis (2 of 39); 19 patients (49%) had no identifiable predisposing factors. Dominant presenting symptoms were abdominal pain (77%), bloody diarrhea (54%), and hematochezia (51%). Most patients were diagnosed at colonoscopy, and most disease was left sided. Twenty-nine patients were successfully managed with intravenous fluids, broad-spectrum antibiotics, and bowel rest; 10 patients required surgery. There was one disease-related death in the operative group. We found a strong female predominance and an association with oral contraceptive use, but almost half of the patients did not have an identifiable etiology. Mortality from ischemic colitis in this patient population is low.