The development of safe arterial access devices and totally implantable or portable infusion pumps for intrahepatic chemotherapy has generated a renewed interest in regional treatment of liver metastases from colo-rectal primaries. Several phase II trials have been carried out, mostly using prolonged infusion of fluorinated pyrimidines showing very high activity for this method of treatment with response rates up to 80%. Randomized trials between systemic and regional therapy have confirmed the higher efficacy of arterial treatment in inducing objective responses but neither of the two studies with a follow-up long enough to assess survival data showed a clear advantage for the patients receiving intraarterial chemotherapy. Gastroduodenitis, ulcers and chemical hepatitis are frequently observed in patients treated with intrahepatic arterial chemotherapy but their incidence can be substantially reduced by a careful surgical procedure during the implant of the arterial catheter and by a close follow-up during chemotherapy. Since toxicity can be serious and no definitive improvement of survival has been shown, this modality of treatment is still applicable only in an investigational setting.