A great deal of attention has been directed recently at the roles played by lipidperoxides in the mediation of pathogenesis and complications of various disease. In view of the strong inhibitory activity of Brazilin on the lipidperoxidation, we examined the effect of Brazilin on the lipidperoxidation in diabetic states. Brazilin inhibited the lipidperoxidation of liver mitochondrial and microsomal fraction in alloxan-induced diabetic ICR mice in the dose and time dependent manner. In the light of the present results, further elucidation of the inhibitory activities of Brazilin on the liver and blood plasma is warrented.