OBJECTIVERed ginseng (RG, Panax ginseng C.A. Meyer) is one of the widely used herbs for treating type 2 diabetes mellitus (DM). However, no systematic review of the effectiveness of RG for type 2 DM is available. This systematic review aimed to evaluate the current evidence for the effectiveness of RG in patients with type 2 DM.

METHODSElectronic searches of 14 electronic databases were conducted without language restrictions. All randomized clinical trials (RCTs) with RG as a treatment for type 2 DM were considered for inclusion. Their methodological quality was assessed using the Cochrane criteria.

RESULTSFour RCTs met our inclusion criteria. Their methodological quality was variable. Three of the RCTs compared the effectiveness of RG with placebo. The meta-analysis of these data failed to favor RG over placebo for fasting plasma glucose (FPG) [n =76, weighted mean difference (WMD): -0.43 mmol/L; 95% confidence interval (CI): -1.16 to 0.30, =0.25] and fasting plasma insulin (FPI) (n =76, WMD: -8.43 pmol/L; 95% CI: -19.54 to 2.68, P =0.14) for 12 weeks of treatment. One RCT compared the effects of RG with no treatment. The results did not suggest favorable effects of RG on FPG, hemoglobin A(1c) (HbA(1c)) or 2-h blood glucose after a meal (PP2h).

CONCLUSIONSThe evidence for the effectiveness of RG in controlling glucose in type 2 DM is not convincing. Few included studies with various treatment regimens prohibit definitive conclusions. More rigorous studies are needed to clarify the effects of RG on this condition.