Fifty-eight patients with colorectal liver metastases were treated by intra-arterial hepatic chemotherapy (IAHC) containing 5 FU (n = 42) or FUDR (n = 16). Twenty-three patients (39.6 p. 100) complained of abdominal pain. In three of these patients, the course was complicated by digestive hemorrhage. Endoscopic explorations and angioscintigraphy were normal in 4, showed oesophagitis in 3, superficial gastritis or duodenitis in 8 (34.7 p. 100) and gastric (2) or duodenal ulceration (6) in 8 (34.7 p. 100). The duodenal ulceration was extensive and considered to be cause of hemorrhage in two cases. Duodenal perforation due to the catheter was discovered in two other cases, one of which was secondary to tumoral extension revealed by forceps biopsy. This patient died 3 months later. Surgical treatment was mandatory in the other case due to digestive hemorrhage but did not prevent death. Angioscintigraphy performed in 15 patients with gastroduodenal inflammation or ulceration was normal in 7 patients, revealed arterial thrombosis in 5 and an extra-hepatic perfusion in the gastroduodenal area in 3 : this was related to a small pyloric artery which was occluded secondarily. IAHC was continued there after. This experience underlines the importance of exploring patients with digestive symptoms during IAHC so that it may be temporarily discontinued while an inadequately positioned infusion catheter may be corrected should gastroduodenal ulceration occur.