The protective effect of omija methanol extract on benzo(a)pyrene induce liver injury was studied in rats in vitro and in vivo. In vitro experiment, primary cultured hepatocytes(5${ imes}$105cells/$mell$) were cultured for 20∼24 hours after adding omija methanol extract(5.1$mu extrm{g}$/$mell$) and B(a)P(50$mu extrm{m}$) in culture medium. In vivo experiment, omija methanol extract(0.1g/kg/day, per os) was administered for 7days and B(a)P(0.1mg/kg body weight, intraperitoneally) was given to the rats after the last administration of extract. Omija methanol extract significantly recovered serum enzyme activities(AST, ALT and LDH) and lipid contents(total cholesterol, triglyceride and HDL-cholesterol) changed by benzo(a)pyrene (B(a)P) to normal levels in vivo. In vitro experiment, as a result of 3-(4, 5-dimethlythiazol-2-yl)-2, 5-diphenyl tetrazolium bromide(MTT) assay, omija methanol extract showed a little hepatotoxicity compared with group I (normal) but significantly recovered enzyme activities(AST, ALT and LDH) changed by B(a)P in comparison to group IIadministered B(a)P only. It was suggested that omija methanol extract has a protective effect on liver injury induced by B(a)P.