The safety of Chinese herbal medicine: a pilot study for a national survey

The aim of this study was to establish the feasibility of conducting a national safety survey involving patients of herbalists monitoring and reporting adverse events associated with the routine practice of Chinese herbal medicine.

In June 2004, 549 herbalists who were members of the UK Register of Chinese Herbal Medicine were invited to ask 10 consecutive patients to participate in the survey. Consenting patients returned their baseline survey forms direct to the research center. Four (4) weeks later, patients were sent a follow-up questionnaire in which they reported adverse events that they perceived were caused by the Chinese herbal medicine over the previous 4 weeks. The data were analyzed with regard to types and frequencies of adverse events as well as potential risk factors using multilevel logistic regression and taking into account the clustering of patients with practitioners.

Of the 161 responding practitioners of Chinese herbal medicine, 71 agreed to participate, comprising 13% of the total membership. A total of 194 patients returned baseline questionnaires, an average of 2.7 patients per practitioner, and 144 (74%) patients completed the 4-week follow-up questionnaires. A total of 20 patients, who were treated by 14 of the herbal medicine practitioners, reported 32 adverse events associated with Chinese herbal medicine over the 4-week period (14% of patients, 95% confidence interval [CI]: 9%-20%). No serious adverse events were reported. The most commonly reported adverse events were diarrhea, fatigue, and nausea. When controlling for potential confounders, patients consulting for Chinese herbal medicine for the first time were more likely to report an adverse event than were those who had consulted repeatedly (OR 3.03; 95% CI: 1.03-8.89, p < 0.02).

In this pilot study, the recruitment rate was low, with only 13% of practitioners participating and only 27% of potential patients returning consent forms, raising questions about potential bias. This research has provided some useful data that will assist in the initiation of future studies.