We analyzed the findings on plain abdominal radiographs in 24 patients who had adverse gastrointestinal reactions after chemotherapy with cytosine-arabinoside (Ara-C) for treatment of acute leukemia or non-Hodgkin lymphoma. Ara-C was given with vincristine, VP 16-213, daunorubicin, amsacrine, adriamycin, or corticosteroids in various combinations and dosages. The abnormalities noted on plain abdominal radiographs included paralytic ileus (73%), cecal distension (38%), pneumatosis intestinalis (27%), thickened loops of small bowel (19%), and pneumoperitoneum (8%). One patient had small-bowel ileus simulating an obstruction. In 23%, death was directly related to gastrointestinal complications. Bowel wall erosions, necrosis, and transmural or submucosal hemorrhage were the main findings at autopsy. This experience suggests that plain abdominal radiographs are useful in the diagnosis of gastrointestinal complications associated with chemotherapy with Ara-C.