The objective of this study was to evaluate the hepatoprotective activity against the ethanol-induced cytotoxicity by Antrodia cinnamomea which were produced from a large-scale fermentation. The production of biomass, extracellular polysaccharide(EPS), intracellular polysaccharide (IPS), and triterpenoids was 27.1, 12, 0.7, and 2.0 g/L, respectively, using a 5000-L agiatated bioreactor with 3500L of A. cinnamomeqa medium (ACM). The hepatoprotective effects of the water extract from the mycelia of A. cinnamomea (WAC) were evaluated in vitro using ethanol-induced cytotoxicity on AML12 hepatocytes. The cytotoxicity and the apoptosis-associated phosphatidyl serine redistribution of plasma membrane to AML 12 cells induced by 300 mM ethanol were effectively reduced by adding 500 mg/L of WAC.From the compositional analysis, the major component in WAC was polysacchariodes that showed a high galactose content (70.9 mg/g crude polysaccharide). Hence, the large-scale fermentation was efficient in producing cell mass and its metabolites which were able to protect hepatocytes from the damage by ethanol. (c) 2008 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.