The physicochemical activities of the underground parts of Roso rugosa Thunb (Rosaceae) , which have been used as an antidiabetic in the folkmedicines of Korea , was carried outThe methanol extract from this plant reduced serum Lipid Level the normal rat . When various fractions from the methanol extract was administered to the rat treated with 1% choholesterol and 0.5% cholic aciddiet , the ethyl acetate soluble fraction lowered the serum triglycerideand phospholipid level most remarkably.