One hundred thirty-one patients with hepatocellular carcinoma were subjected to permanent hepatic artery embolization with dextran microspheres (G-25, 50-150 mu). Dextran hepatic artery embolization is indicated for massive, nodular or multinodular hepatocellular carcinoma with total bilirubin less than 3 mg/dl, serum albumin greater than 3.0 g/dl, tumor involvement area less than 50% or without involvement of the main portal vein. Following hepatic angiography a catheter was inserted superselectively into the hepatic artery feeding the tumor. Adriamycin (60-80 mg) or cisplatin (60-100 mg) was infused immediately before embolization. Under fluoroscopic guidance, 0.3-0.5 g of dextran microsphere embolizer permeated with 10 mg of mitomycin C was infused into the feeding artery through the catheter. Dextran microspheres caused marked homogeneous and distal micro-arterial embolization, especially in the arteriole with a caliber of about 100 mu. Dextran microspheres were not resorbed in a period of 16 weeks in humans, thus reducing or preventing the formation of intrahepatic and extrahepatic collaterals after hepatic artery embolization. Dextran hepatic artery embolization was very effective for not only main tumor but also daughter foci or metastatic nodules, as was confirmed histologically in 8 cases. The 1-year, 2-year and 3-year survival rates were 57.0%, 31.4% and 24.2% respectively.