Inhibitory effects of Hyeulbuchuckeutang(H.B.T) On the peroxidations of lecithin-liposomes by active oxygens, hydroxyl radical and superoxide anion, derived from hydrogen $peroxidase-Fe^{2+}$ system and xanthine- xanthine oxidase system. These effects were similar to and stronger than those of catalase, mannitol, superoxide dismutase or $dl-{alpha}-tocopherol$ as a scavenger or an antioxidant. H.B.T. inhibited the peroxidation of lecithin-liposome and active oxygens in concentration-dependent manner. H.B.T. also dose-dependently protected the cell death mduced by tert-butvlhydroperoxide(tBHP) and significantly increased cell viability in the rat normal liver cell (Ac2F). These results suggested that H.B.T might playa protective role in lipid peroxidation by free radicals and tBHP.