Background: Use of Chinese herbal medicine has increased steadily in the West and adverse reactions have been reported. However, information is not readily available on the toxicity of the herbs and the management of poisoning. The goals of this project were to retrieve and evaluate scientific evidence on the toxicity of Chinese herbal medicine, to grade the toxicity of individual herbs, and to summarize relevant herb data via a searchable electronic database.
Methods: English and Chinese primary studies were systematically retrieved via journal abstracting databases and key toxicity texts. Partial translation of published research was achieved via an audited process utilizing data extraction forms. Methods for grading herb toxicity (in therapeutic use or overdose) were developed based on a combination of the quality of reports, severity of adverse reaction, supporting animal studies, extrapolation from pharmacology and empirical evidence.
Results: Good quality studies on the toxicity of Chinese herbs are lacking. In some cases there is insufficient scientific evidence to create an evidence-based grading of the toxicity of individual herbs. Available data have been summarized into detailed monographs. Twelve herb monographs (with a full toxicity profile and grading) have been completed and summary data for all adequate quality papers used in the grading are linked to the monographs.
Conclusions: The resultant database and monographs represent the first reviews specifically on the toxicity of individual Chinese herbs with toxicological grades based on the evidence of published studies. The database and monographs should assist in promoting the safe and effective use of Chinese herbal medicine.