Herbal Product Contamination and Toxicity

Herbal poisoning exposures reported to poison centers increased by 344% after passage of the Dietary Supplement Health and Education Act, with 24412 exposures reported in 2003. Increased toxicity is speculated to be related to lack of child-resistant packaging, new issues of contamination, proliferation of multiple ingredient products, excessive concentration of active ingredients, and discovery of new drug-herb interactions. This review addresses contamination issues such as heavy metals, pharmaceuticals, homeopathic remedies, microbes, insects, environmental chemicals, and mis identification of one plant for another. Toxicity issues covered include carcinogenicity, delay in seeking medical treatmentwhen using herbs to treat serious illness, toxic components, hypersensitivity reactions, hepatotoxins, nephrotoxins, epileptogenic compounds, cardiac toxins, gastrointestinal toxins, and hematologic toxins. Common drug-herb interactions are discussed. The pharmacist plays an important role in patient education and evaluation of potential toxicities related to herbal supplements.