The defatted methanol extract of bark of Diospyros malabarica (DM) at doses of 200 and 400 mg/kg, p.o. showed significant hypoglycemic activity on normal rats. The extract also exerted significant antihyperglycemic effect in alloxan-induced hyperglycemia and resulted in increase in plasma protein content and decrease in alkaline phosphatase, cholesterol and triglyceride levels when compared with those in the diabetic control group. However there were no significant changes in body and kidney weights of the DM extract-treated animals, compared to those of the untreated diabetic rats as a control. However, the DM extract showed a potential antioxidant activity by increasing catalase activity and reducing lipid peroxidation in liver. The results demonstrate antidiabetic activity of the defatted methanol extract of DM bark.