Ge Gen Qin Lian Decoction are one kind of Chinese prescription, and previous study showed they had antidiabetic effects on the clinical patients and no obvious toxicity was found. The purpose of this study was to evaluate the efficacy and safety of different dosage of Ge Gen Qin Lian Decoction in the treatment of type 2 diabetic patients and explore relationship of the dosage and effect and the safety of 3 dosages of Ge Gen Qin Lian Decoction.

two hundred and forty primary diabetic patients will be expected to be recruited, which were divided into different groups in a randomized, doubled blind, dose-paralleled-control multi-centre clinical design. The patients were randomly taken with high-dosage(5 times of low-dosage),mild-dosage(3 times of low-dosage), low-dosage,placebo(4.5% of low dosage) by 2 times every day for 12 weeks. Hemoglobin A1c (HbA1c), Fasting plasma glucose (FPG),postprandial 2 hours plasma glucose(2hPG),insulin(0h,1h,2h),syndrome,symptoms,body mass index (BMI),waist circumference (WC) of these groups were measured and analyzed. Some safety indexes such blood and urine and stool routine examination, electrocardiogram (ECG)and liver and kidney function tests were measured and analyzed during the experiment. The treatment period is 12 week.

Inclusion Criteria:

• Clinical diagnosis of type 2 diabetes mellitus
• 30-65 years old
• HbA1c≥7.0%, and FPG>7.0 mmol/L, but <13.9 mmol/L or 2hPG>11.1 mmol/L
• Informed consent has been signed
• Dampness and Heat in Spleen

Exclusion Criteria:

• The patients accepted diabetic treatment for more than a month continuously
• The patients were treated by drugs in 3 week before they were given test drugs
• Diabetic ketosis, diabetic ketoacidosis or serious inflammation in a month
• The contractive pressure >160 mmHg or diastolic pressure >100 mmHg
• Pregnant, preparing for pregnancy or breast-feeding women
• Mental patients
• The patients whose ALT or AST are >100U/L,and BUN or Cr are abnormal.
• The patients who have serious heart, lung, liver, kidney and brain or other primary complications
• Allergic persons
• The patients who are attending other clinical trial
• The patients who have serious diabetic complications
• The patients who ever attended this clinical trial
• Alcohol and / or psychoactive substances, drug abuse and dependency
• The person maybe loss for some reason such as work or life condition according to the investigator's judgement
• The lipid-lowering or antihypertensive drug dosage and category which the patients are taking could not be kept stable
• The patients who are eating some drugs or health food which can affect the body weight