Mitomycin C microcapsules (MMC-mc), which were developed as a novel drug carrier, have proved to exert a potential therapeutic effect due to both microinfarction and sustained drug action (chemo-embolization), when infused into a tumor supplying arteries. Experimental studies have demonstrated that chemo-embolization with MMC-mc produces a definitely marked and extensive cytotoxicity in target tissues as compared with traditional arterial chemotherapy, embolization or combination of both. Sixty-seven patients with advanced hepatoma were treated with intra-arterial MMC-mc during the period from 1978 to 1982. Since the majority of patients were in far advanced stages, 56 patients received only single or two infusions of an average dose of 20 mg MMC-mc. Objective tumor reduction greater than 25% in area was observed in 22 (40%) of measurable 55 tumors. Elevated serum alpha-fetoprotein in 26 patients improved in 22 (85%). Relative survival rates of 59 patients without distant metastasis were 64% at 3 months, 49% at 6 months and 26% at 12 months. Side effects such as bone marrow depression, decreased liver function, fever, anorexia, pain and infection were experienced in 9 to 39%, but the majority of them were mild and controllable. Our preliminary experience suggests that MMC-mc can be effectively used in treatment of liver tumors as a palliative but also as a preoperative measure. Further clinical trials including controlled study may well demonstrate the advantages of MMC-mc.