Background:Depression in Parkinson's disease(dPD)is closely related to quality of life.Current studies have suggested that Pingchan Granule(PCG)might be effective for treating dPD.Objective:This study determines the efficacy of PCG for depressive symptoms in Parkinson's disease(PD).Design,setting,participants and interventions:This was a randomized,double-blind,placebo-controlled trial,conducted in Longhua Hospital,Shanghai,China.Patients diagnosed with idiopathic PD and clini-cally significant depressive symptoms(defined by a 24-item Hamilton Rating Scale for Depression[HAM-D]score≥8)were included in this study,randomly assigned to PCG or placebo group in a 1:1 ratio and followed for 24 weeks.Main outcome measures:The primary outcome was the change from baseline to week 24 in HAM-D score among the set of patients who completed the study following the treatment protocol(per-protocol set).Secondary outcomes included changes in scores on the Unified Parkinson's Disease Rating Scale(UPDRS)part 2(UPDRS-Ⅱ),UPDRS part 3(UPDRS-Ⅲ),Parkinson's Disease Sleep Scale(PDSS)and Hamilton Rating Scale for Anxiety(HAM-A),between baseline and week 24.Results:Eighty-six patients were enrolled,and 85 patients were included in the per-protocol set.HAM-D scores decreased by an adjusted mean of 11.77(standard error[SE]0.25)in the PCG group and 3.86(SE 0.25)in the placebo group(between-group difference = 7.91,95％confidence interval[7.22,8.80],P＜0.001),in the multivariable linear regression.Improvements in scores on the UPDRS-Ⅱ,UPDRS-Ⅲ,PDSS,and HAM-A scales were also observed.Conclusion:Treatment with PCG was well tolerated and improved depressive symptoms and motor and other non-motor symptoms in PD.Trial registration:Chinese Clinical Trial Register:ChiCTR-INR-17011949.