Despite the long history of their use in traditional Chinese medicine (TCM), poisonings from misuse of Chinese herbs or herbal preparations do occur from time to time. Such incidents have been documented in Chinese and Western medical and pharmaceutical journals. It is of note that “The most common cause of such poisoning is patients’ failure to follow instructions when preparing the decoctions. To save time, they boil the herbs for less than the prescribed length of time, and this may result in serious consequences.” (Leung, 1984).

Like all other drugs, in addition to poisoning from overdose, the abuse or misuse of Chinese herbs can result in acute but particularly long-term (sometimes subtle) side effects. This is indeed the bad side of Chinese herbs.

It is intuitive that some side effects can result from the long-term use of certain Chinese herbs, in that some (small amounts of) harmful impurities are bound to be present in these herbal products. As reflected in an editorial (Angell and Kassirer, 1998) and the Dietary Supplement Health and Education Act passed by the U.S. Congress in 1994, most herbal preparations are untested and unregulated in North America (and elsewhere). Chinese herbal products thus could be mixed with impurities or environmental contaminants. Some herbs could even have been treated with pesticides during their cultivation. Furthermore, extensive clinical trials, if any, on any particular herbal remedy for long-term side effects are either rare or not well documented (e.g., Chan, 1997), despite the claim that these remedies have been time-tested to be safe.