We are still waiting for firm evidence on Chinese herbal medicines for treatment of non-insulin-dependent diabetes. Although the use of herbal medicines for treatment of diabetes has a long history especially in the East, current evidence cannot warrant to support the routine use in clinical practice. This systematic review evaluates the effects of various herbal preparations (including single herbs or mixtures of different herbs) for treating people with type 2 diabetes. The review shows that some herbal medicines lower blood sugar and relieving symptoms in patients with diabetes. However, the methodological quality of the clinical trials evaluating these herbs is generally poor. The analyses also indicate that trials with positive findings are more likely to be associated with exaggerated effects. However, the trials did not report significant adverse effects. In conclusion, herbal medicines should not be recommended for routine use in diabetic patients of type 2 diabetes until we get scientifically sound trials. Testing the herbs in larger, well-designed trials is needed in order to establish the necessary evidence for their use.
Some herbal medicines show hypoglycaemic effect sin type 2 diabetes. However, these findings should be carefully interpreted due to the low methodological quality, small sample size, and limited number of trials. In the light of some positive findings, some herbal medicines deserve further examination in high-quality trials.
Traditional Chinese herbal medicines have been used for a long time to treat diabetes, and many controlled trials have been done to investigate their efficacy.
To assess the effects of Chinese herbal medicines in patients with type 2 diabetes mellitus.
We searched the following electronic databases: The Cochrane Library (CENTRAL), the Chinese BioMedical Database, MEDLINE, EMBASE, and LILACS, combined with hand searches on Chinese journals and conference proceedings. No language restriction was used.
Randomised trials of herbal medicines (with at least two months treatment duration) compared with placebo, pharmacological or non-pharmacological interventions were included.
Data were extracted independently by two reviewers. The methodological quality of trials was evaluated using the parameters of randomisation, allocation concealment, double blinding, and drop-out rates. Meta-analyses were performed where data were available.
Sixty-six randomised trials, involving 8302 participants, met the inclusion criteria. Methodological quality was generally low. Sixty-nine different herbal medicines were tested in the included trials, which compared herbal medicines with placebo, hypoglycaemic drugs, or herbal medicines plus hypoglycaemic drugs.
Compared with placebo, Holy basil leaves, Xianzhen Pian, Qidan Tongmai, traditional Chinese formulae (TCT), Huoxue Jiangtang Pingzhi, and Inolter showed significantly hypoglycaemic response. Compared with hypoglycaemic drugs including glibenclamide, tolbutamide, or gliclazide, seven herbal medicines demonstrated a significant better metabolic control, including Bushen Jiangtang Tang, Composite Trichosanthis, Jiangtang Kang, Ketang Ling, Shenqi Jiangtang Yin, Xiaoke Tang, and Yishen Huoxue Tiaogan. In 29 trials that evaluated herbal medicines combined with hypoglycaemic drugs, 15 different herbal preparations showed additional better effects than hypoglycaemic drugs monotherapy. Two herbal therapies combined with diet and behaviour change showed better hypoglycaemic effects than diet and behaviour change alone. No serious adverse effects from the herbal medicines were reported.