Preliminary results of a prospective non-randomized trial of prophylactic hepatic arterial chemotherapy for liver metastases from colorectal cancer are presented. Twenty-two colorectal cancer patients (infusion group) in Dukes' C stage were given hepatic arterial infusion of 5-FU (500 mg/body for 1 hr per week, repeated 50 times) and peroral UFT-E (2.0 g/body, daily). Informed consent was obtained from all patients. Adverse effects and postoperative recurrence in the infusion group were compared with those of patients with UFT-E alone (control group). Complications related to hepatic arterial infusion in the infusion group were also demonstrated. There was no adverse effect in the control group, while diarrhea (grade 1) developed in one patient (5%) and pigmentation in five (24%) in the infusion group. Complications related to infusion were found in five patients (5%). Three patients in the infusion group presented with metachronous hepatic lesions, two of which were resected successfully. In the control group, one patient died of marked hepatic metastases, and one developed ovarian metastasis with lymph node involvement. Our regimen appears hematologically safe, however, the high frequency of pigmentation should be kept in mind. The oncological benefit of this chemotherapy would be clarified by a larger series of cases and longer follow-up.