Objective To study the effect of Wentang Granule（Granule for Stabilizing Glucose） on impaired glucose tolerance（IGT） of type Ⅱ diabetes.Methods Totally 150 patients with diagnosis of IGT were randomly divided into 3 groups:education group

observation group

and control group

with 50 cases in each.They were treated with guidance on life style

Wentang Granule

and Acarbose respectively and observed for 2 years.The observed indexes included fasting blood glucose（FBG）

serum lipid

body mass index（BMI）

waist hip ratio（WHR）

changes of TCM symptoms and scores.The therapeutic effect was evaluated with the changes of glucose tolerance.Results After treatment

the conversion rate of normal glucose tolerance and diabetes of the observation group and control groups was significantly different from that of the education group（P <0.05 or P<0.01）.In the observation group

the FBG

serum lipid

BMI

WHR

TCM symptoms and scores were significantly different from those before treatment and those of the education group after treatment（P <0.05 or P<0.01）.And the triglyceride（TG）

high density lipoprotein cholesterol（HDL-C）

and TCM symptoms and scores were significantly different from those of the control group after treatment（P <0.05 or P<0.01）.Conclusion Wentang Granule can control carbohydrate and lipid metabolism to relieve symptoms

and can reduce the incidence of conversion of IGT to diabetes type Ⅱ.