G009, a polysaccharide isolated from the mycelia of Ganoderma lucidum IYO09, showed a hepatoprotective activity against $CCl_4$ induced cytotoxicity in primary cu ltured rat hepatocytes. Incubation of $CCl_4$-intoxicated hepatocytes with G009 significantly reduced the levels of glutamic pyruvic transaminase and sorbitol dehydrogenase released from hepatocytes in the medium. G009 showed antioxidative effect by elevating the activities of glutathione reductase and superoxide dismutase, and the content of glutathione in $CCl_4$-intoxidcated primary cultured rat hepatocytes. Furthermore, G009 significantly elevated glutathione-S-transferase activity in $CCl_4$-intoxicated primary cultured rat hepatocytes. G009 also reduced the production of malondialdehyde, a byproduct of lipid peroxidation. From these results, it could be concluded that G009 exerted hepatoprotective activity against $CCl_4$-induced cytotoxicity through antioxidation.