Sesamol is a kind of antioxidant and exists in sesame oil. This paper describes the protective effect of sesamol against carbon tetrachloride (CCl4)-induced liver injury in rats. Sesamol had a significant effect in case of intraperitoneal, subcutaneous and oral administration. In order to examine the relationship between the chemical constitution of sesamol and its protective effect, the protective effects of 20 kinds of sesamol related compounds against liver injury induced by CCl4 were investigated in rats. Consequently, significant protective effects were found in methylenedioxybenzene, isosafrole, safrole, methylenedioxyaniline and methylenedioxyacetophenone. These five compounds had a methylenedioxy group had protective effects, it was considered that the protective effects of the methylenedioxy group were influenced by substituent groups on 4 position of methylenedioxy phenyl compounds. In addition, sesamol, methylenedioxybenzene and isosafrole showed significant protective effects against cholestasis induced by CCl4.