Effects of Schisandrin B (Sch B) and alpha-tocopherol (alpha-TOC) on ferric chloride (Fe3+) induced oxidation of erythrocyte membrane lipids in vitro and carbon tetrachloride (CCl4) induced lipid peroxidation in vivo were examined. While alpha-TOC could produce prooxidant and antioxidant effect on Fe(3+)-induced lipid peroxidation, Sch B only inhibited the peroxidation reaction. Pretreatment with alpha-TOC (3 mmol/kg/day x 3) did not protect against CCl4-induced lipid peroxidation and hepatocellular damage in mice, whereas Sch B pretreatment (0.3 mmol/3.0 mmol/kg/day x 3) produced a dose-dependent protective effect on the CCl4-induced hepatotoxicity. The ensemble of results suggests that the ability of Sch B to inhibit lipid peroxidation, while in the absence of pro-oxidant activity, may at least in part contribute to its hepatoprotective action.