Fifteen patients with liver metastases of colorectal cancer were entered in our study, and 5-FU was given continuously by hepatic intra-arterial route at 1 g/day over 6 days. No leukopenia (< 3,000/mm3), anemia (< 10 g/dl), or thrombocytopenia (< 75,000/mm3) occurred, and no elevation of serum AST (> 150 IU/l) or serum T-Bil (> 2 mg/ml) appeared. One patient (4.2%) had nausea with vomiting 1-5 per day, and another (4.2%) had mucositis requiring treatment. In patients with multiple liver metastases, survival of the continuous infusion group [total dose of 5-FU > or = 12 g] (n = 5) seems to be longer than those of the hepatectomy only group (n = 3) or the control group (n = 7). We suggest that this continuous intra-arterial infusion of high-dose 5-FU is a useful chemotherapy with few side effects or complications.