Toxicity of Herbs, Vitamins, and Supplements.

In the United States, the Food and Drug Administration regulates the efficacy and safety of pharmaceutical drugs. This government agency was formed in direct response to a mass poisoning and more than 100 deaths from kidney failure due to a medicinal toxic alcohol exposure. In contrast, the Food and Drug Administration also regulates the use of vitamins, minerals, herbs, or botanicals as dietary supplements, banning specific medical claims but requiring no documentation of efficacy. Safety of dietary supplements is only ensured through reporting of adverse events and rarely through intervention. Consumers should be aware that supplements may in fact contain actual pharmaceuticals or nothing of value and have significant toxic potential. Toxicity due to Chinese herbal medicines, aristolochic acid, amygdalin, hypervitaminosis D, and heavy metal contamination is reviewed.