We evaluated the hepatoprotective activity of crude hot-water extracts of the traditional Korean medicinal herb, Phellodendri Cortex (PC; Bark of Phellodendron amurense RUPR.), in an experimental model of hepatic damage induced by carbon tetrachloride ($CCl_4$). The serum marker of liver damage, sGOT, sGPT and sALP, were significantly decreased in the liver of the PC treated rats, compared with that of $CCl_4$ treated group. The histological observation of liver section of rats, showed the same protective effect of PC treatment. And the protective activity of PC was more significant in the post-treated group than pre-treated group. The significant decrease of malodialdehyde and increase of glutathion, catalase activity were observed in the liver homogenate of PC treated rats. Based on these findings, it is suggested that PC has potent hepatoprotective effects and the mechanism of the protection may be related to antioxidation pathways.