A U.S. perspective on the adverse reactions from traditional Chinese medicines

Traditional Chinese medicines (TCM) are popular in the United States and Asian and non-Asian consumers are using the product for disease treatment and health prevention. As more people are using TCM products, there are increased reports on adverse reactions. This review will focus on adverse reactions due to TCM as reported in the literature.

The review is based on MedLine search of literatures using keywords including: herbs, herbal, traditional Chinese medicines with toxicity, adverse effects, death, drug interaction and pharmacokinetic. In addition, specific searches were performed using the above keywords with the common name and the scientific name of the plant product.

The causes of adverse reactions associated with TCM are diverse. They include variability in active/toxic ingredients due to growing conditions, use of inherent toxic herbs causing toxicity, overdose of herbs, drug-herb interactions especially with pharmaceuticals that have narrow therapeutic index, coexisting diseases, and idiosyncratic reactions like allergy, hepatitis and anaphylaxis. Other adverse reactions can be due to manufacturing and quality problems causing adulteration, misidentification, substitution of one herb with another, variability in the amount of active ingredients, use of pharmaceuticals without identifying on the labels, improper processing and preparation, and contamination.

To minimize the adverse reactions from TCM and protect the public, there must be adequate laws and regulations to ensure that products are manufactured with the highest standards. Manufacturers should be licensed by regulatory agency and manufactured under good manufacturing practice. TCM products must be evaluated for their safety before marketing. Proper labeling and good surveillance systems shall ensure the protection of the consumers.