Double Randomized and Placebo Controlled Trail of Tianqi Pingchan Granule to Prevent Levodopa-Induced Dyskinesia

Inclusion Criteria: Patients with PD aged 30-85，have at least the following two conditions:

1. Dosage of Levodopa ≥ 400mg/d;

2. Grade of H&Y≥3;

3. risk score of dyskinesia>4;

Exclusion Criteria:

1. PD patients with dyskinesia;

2. Taking other Chinese medicines against Parkinson's disease;

3. pregnant and lactating women;

4. Impaired cognitive function (according to pre-entry MMSE score): secondary education level: MMSE <24 points; primary education level <20 points;illiterate <17 points;

5. accompanied by a history of mental illness;

6. impaired liver and kidney function;

7. accompanied by severe other systemic diseases;

8. Previous traditional Chinese medicine preparations or serious adverse reactions

9. Before the enrollment, the EKG showed obvious abnormalities and required clinicalintervention.

10. PD related brain surgery

11. Patients who are participating in other clinical studies or has participated otherclinical studies within 30 days before

12. Patients unable to cooperate with the survey