Regulatory issues relating to herbal products - Part 2: Safety and toxicity

A significant proportion of the general public has the misconception that herbal products are safe because they are of natural origin. Toxicity may arise from inherent properties of the herbal ingredients that result in adverse reactions, which may be serious, or from interactions with conventional drug substances. Toxicity may also be caused by misuse, abuse, and overuse of products and by adulteration of products or misidentification of plants. Regulatory authorities are undertaking to provide a reasonable assurance of efficacy and improved safety of herbal products through monitoring programs and control of herbs that are known to be toxic. Action is taken by the authorities to protect public health when herbal preparations are shown or suspected to cause harm. Case reports of toxicity due to herbal products and actions taken by regulatory authorities are summarized in this article. In the European Union, applicants for marketing authorizations may be required to provide scientific proof of safety and efficacy by reference to bibliographic data, where available. The relevance and credibility of published data needs to be assessed against recommended criteria in order to avoid unnecessary repetition of tests on animals or humans.