Impaired glucose tolerance(IGT) & Impaired fasting glucose(IFG) were standardized in 1979 by the National Diabetes Data Group and the World Health Organization as a risk factor for type 2 diabetes. The main clinical significance of IGT & IFG shows some risk factors on type 2 diabetes, cardiovascular disease and component of the metabolic syndrome. In 1997, the American Diabetes Association(ADA) proposed the new classification and diagnostic criteria for diabetes, which wss striction on the diagnostic baseline of Diabetes from 140 mg/dl to 126 mg/dl. This is because that the early diagnosis and treatments can prevent chronic complications. In the oriental medicine, Gamiyookmigihwang-tang has been using for the treatments of Diabetes including IGT & IFG; however, there have not been enough studies about the effect of the glycemic control objectively. So clinical studies have been performed on a mild DM(Diabetes Mellitus) patient with IGT and IFG in order to investigate whether there is hypoglycemic effect of Gamiyookmigihwang-tang. Prior to the study, for two weeks fasting blood sugar(FBS) and postprandial 2hrs(PP2hrs) glucose were checked. in addition ECG, T-cholesterol, TG, HbA1c levels were measured; then, Gamiyookmigihwang-tang has administrated for 4 weeks. and FBS, PP2hrs, T-cholesterol, TG, HbA1c were measured again after the herb medicine treatment. FBS, PP2hrs glucose levels and other measuring levels (T-cholesterol, TG, HbA1c) were decreased by the administration of Gamiyookmigihwang-tang. Gamiyookmigihwang-tang has hypoglycemic effects on a mild DM patient with IGT and IFG.