We studied the effects of the methanolic extracts and fractions from leaves, fruits, stems and roots of Curadrania tricuspidata on the formation of lipid peroxide. The methanol extracts of leaves, fructus and stem of this plants decreased the formation of lipid peroxide in the isolated rat liver. The ethyl acetate fraction of leaves and n-butanol fraction of stems reduced the lipid peroxide formation. It showed that arthocarpesin, one of the constituents isolated from this plant, lowered the formation of lipic peroxide by 13%, 21%, 22% and 25% at the concentration of $10^{-8},;10^{-6},;10^{-4};and;10^{-2}mg/ml$, respectively.