Review of Randomized Controlled Trials
Tae-Hun Kim1,2, Ki-Ho Cho1*, Woo-Sang Jung1, Myeong Soo Lee2
1 Department of Cardiovascular & Neurologic Diseases, College of Oriental Medicine, Kyung Hee University, Seoul, South Korea, 2 Korea Institute of Oriental Medicine,
Daejeon, South Korea
Objective: We conducted systematicreview to evaluate current evidence of herbal medicines (HMs) for Parkinson’s disease
Methods: Along with hand searches, relevant literatures were located from the electronic databases including CENTRAL,
MEDLINE, EMBASE, CINAHL, AMED, PsycInfo, CNKI, 7 Korean Medical Databases and J-East until August, 2010 without
language and publication status. Randomized controlled trials (RCTs),quasi-randomized controlled trials and randomized
crossover trials, which evaluate HMs for idiopathic PD were selected for this review. Two independent authors extracted
data from the relevant literatures and any disagreement was solved by discussion.
Results: From the 3432 of relevant literatures, 64 were included. We failed to suggest overall estimates of treatment effects
on PD because of the wideheterogeneity of used herbal recipes and study designs in the included studies. When compared
with placebo, specific effects were not observed in favor of HMs definitely. Direct comparison with conventional drugs
suggested that there was no evidence of better effect for HMs. Many studies compared combination therapy with single
active drugs and combination therapy showed significant improvementin PD related outcomes and decrease in the dose of
anti-Parkinson’s drugs with low adverse events rate.
Conclusion: 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.
Citation: Kim T-H, Cho K-H, Jung W-S, Lee MS (2012) HerbalMedicines for Parkinson’s Disease: A Systematic Review of Randomized Controlled Trials. PLoS
ONE 7(5): e35695. doi:10.1371/journal.pone.0035695
Editor: Mark R. Cookson, National Institutes of Health, United States of America
Received December 6, 2011; Accepted March 21, 2012; Published May 15, 2012
Copyright: ß 2012 Kim et al. This is an open-access article distributed under the terms of theCreative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: The authors have no support or funding to report.
Competing Interests: The authors have declared that no competing interests exist.
* E-mail: firstname.lastname@example.org
in over eighties . Considering that medicalexpenditure for PD
is one of the highest ranked neurologic diseases, PD might be a
serious socioeconomic burden in future aging society [5–7].
Herbal products for PD have been used worldwide in traditional
medicine . Especially in China, records of herbal prescriptions
for treating PD might date back to about 2200 years ago  and
current literatures reflect active use of HM for PD until now[10,11]. Practitioners and patients employ HM as an adjuvant
therapy of conventional treatment for the purpose of reducing
dose of dopaminergic drugs, adverse event related to prolonged
usage of dopaminergic agents and improving PD symptoms .
Previous literature reviews have been evaluated the clinical
evidence of HM including traditional Chinese medicine (TCM)
[9,10,12,13]. However thesereviews did not adopt explicit search
strategy so all the possible studies might not be located.
Information on the herbal remedies was not presented in details.
In addition, any results on the effect size were not reported. From
these limitations, these reviews failed to suggest the global picture
of HMs for treating PD [9,10,12,13].
The purpose of this review is to evaluate the current...