Wood vinegar, an extract from Acer Tegmentosum Maximowicz, was evaluated for its hypoglycemic andanti-diabetic properties by using normal and diabetic rats. The extract was dissolved in water andadministered daily for six or seven weeks. In experiment 1, thirty normal Sprague-Dawley (SD) male rats wererandomly divided into five treatments of 6 rats each. The treatments were T1 (mineral water), T2 (mineralwater), T3 (silver solution), T4 (wood vinegar), and T5 (silver solution + wood vinegar) and diabetes wasinduced by intravenous injection of streptozotocin except T1. In experiment 2, sixteen diabetic Goto-Kakizaki(GK) male rats were randomly divided into four treatments of 4 rats each. The treatments were T1 (mineralwater), T2 (silver solution), T3 (wood vinegar), and T4 (silver solution + wood vinegar).Streptozotocin-induced diabetic rats showed less body weight gain, more food intake and less waterconsumption as compared with normal non-diabetic rats. Oral administration of wood vinegar resulted inmore weight gain, lower blood glucose concentration and urine pH among all the diabetic rats. In experiment2, diabetic GK rats administrated with wood vinegar showed higher weight gain, food intake and less waterintake when compared with control. However, supplementation with wood vinegar did not result in anydecrease of blood glucose concentrations. It could be concluded that wood vinegar extracted from AcerTegmentosum Maximowicz exerted hypoglycemic effect in diabetic-induced normal rats, but not in diabetic GKrats.