Hepatic artery infusion chemotherapy is a recognized treatment of unresectable hepatic neoplasms. Because the arterial supply to the stomach and duodenum originates from the celiac and hepatic arteries, unavoidable infusion of the gastroduodenal and right gastric arteries may result in gastrointestinal complications. Of 174 patients (266 infusions) treated with hepatic artery infusion chemotherapy during a 12 month period, 18 developed severe dyspepsia. Ten of these 18 patients had gastrointestinal pathology documented by either endoscopy or upper gastrointestinal series; six had gastric ulcer and gastritis, two had duodenal ulcer, one pyloroduodenitis, and one pancreatitis. Endoscopically, the hepatic artery infusion chemotherapy-induced ulceration and gastritis were located in the distribution of the infused arteries. Radiographically, the gastric abnormalities ranged from typical benign ulcers to a pattern of multiple ulcerations with nodular fold mimicking malignancy. Angiographic correlation could be made on eight of the 10 patients. Vascular trauma, observed in five of these eight patients, seemed to contribute to gastrointestinal complications in hepatic artery infusion chemotherapy.