Abstract: The antioxidative effect of three water-soluble components isolatedfrom Salvia miltiorrhiza has been investigated. All the three components were found to in-hibit both NADPH-vit C and Fe²⁺ - cysteine induced lipid peroxidation (malon-dialdehyde formation) in rat brain, liver and kidney microsomes in vitro . The order oftheir inhibitory effect is as follows: salvianolic acid A, salvianolic acid B and rosmarinicacid. The inhibitory effect on lipid peroxidation induced by NADPH-Vit C was morethan that induced by Fe²⁺- cysteine. In addition, the three compounds lowered the produc-tion of superoxide anion radical (O₂) in xanthine- xanthine oxidase system. The order oftheir potency was similar to that in antilipoperoxidation. The above results suggest thatthe three components have strong antilipoperoxidant activity in vitro, which may be partlythrough scavenging O₂.