Two cases of severe upper G-I bleeding associated with hepatic 5-PU infusion are presented. This bleeding originated from duodenal ulcers caused by perforation of the gastroduodenal artery by the infusion catheter. They were visualized both at angiography which showed contrast leakage to the duodenum, and at gastroscopy, where the infusion catheter could be seen in the ulcer crater. The incidence and possible pathogenesis of peptic ulcer disease following hepatic infusion chemotherapy is discussed.