Toxicological Risks of Chinese Herbs

As traditional Chinese medicine (TCM) has become more popular there have been increasing concerns about safety and potential toxicity of the Chinese materia medica (CMM) comprising plants, animal parts and minerals. The potential toxicity of many CMM is well recognised in TCM and to reduce risks use of some herbs is restricted whilst specific processing methods have been developed to modify the activities/toxicity of others. However adverse reactions have been reported, many of these are due misuse or abuse of Chinese medicine. The main problem remains products adulterated with pharmaceuticals for weight loss or erectile dysfunction. But some herbs have narrow therapeutic ranges (e. g., Aconitum species) so toxic effects are frequently reported. Toxic effects from chronic or cumulative dosing are difficult to detect in the traditional setting and recent reports have demonstrated the health problems from Aristolochia species. Despite safety concerns, Chinese medicine appears to be relatively safe with comparatively few reports of adverse reactions compared with overall drug reports. The wealth of information in the Chinese literature needs to be more widely available. As TCM is widely used by patients, improved pharmacovigilance and pharmacoepidemiology can contribute valuable safety information, relevant to clinical use.