Objectives : So-Dang-Hwan (SDH) is used as a traditional treatment of diabetes in oriental clinics in Korea. This study aimed to evaluate antidiabetic effect of SDH in streptozotocin (STZ)-induced diabetic rats. Methods : Diabetes was induced by i.p. injection of STZ (45 mg/kg) to Sprague-Dawley rats. Experimental animals (eight per group), were treated by oral administration of SDH (60 mg/kg body weight) and glibenclimide (1 mg/kg), a known antidiabetic drug for comparison, during 5 weeks. To veridy the effect of SDH, the levels of glucose, triglyceride, insulin, BUN and creatinine were measured in sera from experimental diabetic rats, and an oral glucose tolerance test (OGTT) was also performed. Results : SDH prevented body weight loss in diabetic rats. SDH exhibited at termination, a significant reduction in blood glucose levels in STZ-induced diabetic rats. SDH significantly reduced serum creatinine levels toward the normal levels. The OGTT results showed a significant improvement in glucose tolerance in rats treated with SDH. Conclusions : These data indicate that SDH treatment may improve glocose homeostasis in STZ-induced diabetes.