An extracorporeal bioartificial liver (BAL) that could prevent death from hepatic encephalopathy in acute hepatic insufficiency was aimed to develop. A functional human hepatocellular carcinoma cell line (FLC-4) was cultured in a radial-flow bioreactor. The function of the BAL was tested in mini-pigs with acute hepatic failure induced by alpha-amanitin and lipopolysaccharide. When the BAL system was connected with cultured FLC-4 to three pigs with hepatic dysfunction, all demonstrated electroencephalographic improvement and survived. Relatively low plasma concentrations of S-100 beta protein, as a marker of astrocytic damage, from pigs with hepatic failure during BAL therapy were noted. BAL therapy can prevent irreversible brain damage from hepatic encephalopathy in experimental acute hepatic failure.