To compare the efficacy of hepatic arterial (HA) and portal venous infusion (PV) anticancer drugs in the prevention of the liver metastasis of cancer, the following experimental study was performed. VX2 tumor cells (1 x 10(7) cells) floating in physiological saline were injected into the portal vein of Japanese white rabbit. Adriamycin (ADR) was administered to the liver via HA or PV at 3, 5, 7 (1 mg/kg) days, and immediately, 2, 4 days after tumor inoculation, respectively. The rabbits were sacrificed 3 weeks after tumor inoculation and the total number of liver metastases was counted. Results were as follows: 1) The numbers of metastatic VX2 tumor nodules in HA group were significantly smaller than in PV group (p = 0.05). 2) Starting ADR injection immediately after tumor inoculation enhanced the inhibition of tumor growth. These results suggest that immediate hepatic arterial infusion of anticancer drugs after resection of primary gastrointestinal cancer is most useful to prevent liver metastases.