improvement in drug response and reduction of toxicity were observed after continuous intrahepatic arterial infusion of mytomycin-C (MMC) and 5-fluorouracil (5-FU) in 15 of 26 patients with primary or metastatic carcinoma of the liver. Serum bilirubin values of 10 mg/100 ml absence of ascites, extreme cachexia and impending hepatic failure were used as the criteria for admission of these patients into the study. The patients were given MMC in a dose of 0.08 mg/kgon day 1,5-FUin a dose of8-10 mg/kgon days2-5,and MMCon day6. This schedule was reinitiated on days 8 and 15 for a total mean duration of 18 days. Maintenance therapy was carried out by the administration of these drugs at induction dosage alternated each week as a single 24 hourly intravenous infusion. Objective response to combination therapy was defined as decrease of at least 50% in the liver size and in the abnormal levels of serum alkaline phosphatase and glutamic oxaloacetic transaminase (SGOT) , and near normal levels of serum bilirubin for a minimum period of 2 months. The duration of objective response ranged from 3-16 months with a median of8.2 months. The median survival time for the responders was 7.2 months for patients with primary carcinoma and 9.4 months for patients with metastatic carcinoma of the liver as compared to 2 months for patients who failed to respond to the treatment. Five out of 12 patients who were refractory to MMC or 5-FU by intravenous infusion responded to the present combination drug therapy. Of four patients who died during induction therapy, three had liver failure and the fourth suffered pulmonary embolism. These studies provide evidence that combination therapy with MMC and 5-FU increases the survival time of patients with hepatic cancer, presumably due to the synergistic action of these drugs which permits the use of a low dosage schedule and has less toxic effects.