Background: For its better differentiated hepatocyte phenotype, C3A cell line has been utilized in bioar- tificial liver system. However, up to now, there are only a few of studies working at the metabolic alter- nations of C3A cells under the culture conditions with liver failure plasma, which mainly focus on car- bohydrate metabolism, total protein synthesis and ureagenesis. In this study, we investigated the effects of acute liver failure plasma on the growth and biological functions of C3A cells, especially on CYP450 enzymes.Methods: C3A cells were treated with fresh DMEM medium containing 10％ FBS, fresh DMEM medium containing 10％ normal plasma and acute liver failure plasma, respectively. After incubation, the C3A cells were assessed for cell viabilities, lactate dehydrogenase leakage, gene transcription, protein levels, albu- min secretion, ammonia metabolism and CYP450 enzyme activities. Results: Cell viabilities decreased 15％, and lactate dehydrogenase leakage had 1.3-fold elevation in acute liver failure plasma group. Gene transcription exhibited up-regulation, down-regulation or stability for different hepatic genes. In contrast, protein expression levels for several CYP450 enzymes kept constant, while the CYP450 enzyme activities decreased or remained stable. Albumin secretion reduced about 48％, and ammonia accumulation increased approximately 41％. Conclusions: C3A cells cultured with acute liver failure plasma showed mild inhibition of cell viabilities, reduction of albumin secretion, and increase of ammonia accumulation. Furthermore, CYP450 enzymes demonstrated various alterations on gene transcription, protein expression and enzyme activities.