Herbal Medicines for Parkinson's Disease: A Systematic Review of Randomized Controlled Trials
"Many studies compared combination therapy with single active drugs and combination therapy showed significant improvement in PD related outcomes and decrease in the dose of anti-Parkinson's drugs with low adverse events rate... Currently, there is no conclusive evidence about the effectiveness and efficacy of HMs on PD. For establishing clinical evidence of HMs on PD, rigorous RCTs with sufficient statistical power should be promoted in future."
 Kim T-H, Cho K-H, Jung W-S, Lee MS (2012) Herbal Medicines for Parkinson's Disease: A Systematic Review of Randomized Controlled Trials. PLoS ONE 7(5): e35695. doi:10.1371/journal.pone.0035695, 2012.