Gastrointestinal complications in acute leukemia have been infrequently reported. Reported here is a review of all patients on the hematology teaching service with acute leukemia from 1974 to 1980 and those with intestinal complications. Of the 50 patients with acute leukemia, 14 (28%) developed an acute abdominal catastrophe. They presented with an acute surgical abdomen, diarrhea, gastrointestinal bleeding, and a paralytic ileus. All were granulocytopenic and thrombocytopenic. All but one episode was associated with the death of the patients; survival ranged from 4 to 26 days (median 9 days) after their last dose of chemotherapeutic drugs. Cytarabine was administered in 13 of the 14 patients. It is believed that bowel necrosis which causes death in acute leukemia occurs more frequently than previously thought. There is a close association of the clinical syndrome with chemotherapeutic drugs, especially cytarabine.