The object of this study was to observe the effects of Hwanggeum-tang (HGT) aqueous extracts on Streptozotocin-induced rat's diabetes and related complications. Three different dosages of HGT extracts were orally administered oncea day for 28 days from 3 weeks after Streptozotocin treatment (60 mg/kg, single intraperitoneally administered). All the rats were checked at 3 weeks after Streptozotocin treatment as follows. Changes on the body weight, blood glucose level, kidney weight, serum BUN and creatinine level, liver weight, serum AST and ALT level, serum LDL, HDL, triglyceride and total cholesterol level were observed with changes on the pancreatic MDA content and GSH content. The results were compared with a potent antioxidant silymarin 100 mg/kg in which the effects on Streptozotocin-induced diabetes and related complications were already confirmed. As results of Streptozotocin-injected diabetes and related complications, dramatical decreases on the body weight, increase of the kidney and liver weight, increase of serum BUN, creatinine, AST, ALT, LDL, triglyceride, total cholesterol level and decreases of serum HDL level were detected in streptozotocin control as compared with intact control. In addition, marked increases of pancreatic MDA content and decreases of GSH content were also detected in streptozotocin control as compared with intact control. However, these diabetes and related complications, and inhibition of antioxidant effects induced by Streptozotocin were inhibited by 28 days continuous treatment of 50, 100 and 200 mg/kg of HGT extracts in the present study. HGT have favorable effects on the diabetes and various diabetic complications. Therefore, more detail mechanism studies should be conducedin future with the efficacy tests of individual herbal composition of HGT and the screening of the biological active compounds in herbs.