A randomized, double-blind, placebo-controlled multicenter clinical trial was used to observe the effectiveness, safety and side effects of Tianqi Pingzhan Granule in the prevention of levodopa induced dyskinesia, so as to determine the clinical efficacy of Tianqi Pingzhan Granule in the prevention of levodopa induced dyskinesia.

The aim of this clinical trail is to evaluate the effect of Tianqi Pingzhan Granule in the prevention of levodopa induced dyskinesia in adults. All patients included in the study should meet the inclusion criteria. Half of participants will receive Tianqi Pingzhan Granule, while the other half will receive a placebo of Tianqi Pingzhan Granule. All participants will be assigned to either the active group or the control group randomly. During the clinical trail both doctors and patients are double-blind except serious adverse events occurred.

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 clinical intervention.

10. PD related brain surgery

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

12. Patients unable to cooperate with the survey