A phase II study of weekly intermittent hepatic arterial infusion of high dose 5-FU for liver metastases from colorectal cancer was carried out. Thirty-two patients with unresectable liver metastases from colorectal cancer were entered in this study. Nausea (< or = grade 2) was observed in 31% of the cases, mild elevation of rGTP in 13%, biloma in 9%, and hepatic arterial occlusion in 22%. However, no major toxicity occurred. The response rate evaluated by CT-scans was 75% (4 CR + 20 PR/32), and the overall median survival was 22 months. Significant differences of median survival were observed in the extra-hepatic lesions [extrahepatic lesions: (-) 16 months vs (+) 22 months]. This regimen showed high activity without major toxicity and the reduction of pts' QOLs caused by pumps. It confirmed by a study involving a large number of cases, this regimen will become a standard regimen for unresectable liver metastases from colorectal cancer.