Objective: To provide an overview of the most common contaminants that cause problems in herbal medicines, with specific examples of the problems encountered in the United Kingdom. Additionally, some of the measures taken to help address these problems are discussed. Methods: The flourishing herbal market in the UK currently comprises of several different types of herbal medicines. These originate from different parts of the world for example Europe, China, India, America and Africa. Herbal medicines or herbal medicinal products as they are frequently referred to, are medicinal products containing single or several herbal substances or herbal preparations. In order to guarantee the quality of herbal preparations and herbal medicines, the herbal substance/s must be of high quality and free of impurities. This unfortunately is not always the case and the most common forms of contamination arise from foreign organic matter such as small amounts of related parts of plant or other plants, insects or other animal matter, microbial contamination, pesticides, fumigants, fungicides, mycotoxins, inorganic and toxic metals (1). Contamination by adulteration/substitution or with toxic compounds also contributes to numerous problems. The safety implications of the problems experienced due to contamination of herbal medicines varies enormously, largely depending on the type and level of contaminant, the patient population taking the product and the dose taken. In the worse case scenario contaminated products have led to irreversible organ damage and even death. Over the past years, the UK has had to increasingly deal with cases resulting from contaminated herbal medicines with toxic metals (arsenic, mercury, lead), microbial sources, adulteration/substitution with other plant species for example Aristolochia or with prescription medicines such as corticosteroids. Results: The quality of herbal medicines is a major concern with regard to the safety of herbal products, especially in a notably unregulated market. A significant step aimed at reducing the problems encountered with contamination is the EU Directive on Traditional Herbal Medicinal Products 2004/24/EC that came into force in 2004. Under this Directive, a simplified registration procedure is provided for traditional herbal medicinal products known as the Traditional Herbal Registration Scheme. The quality aspects of the product and manufacture are fully controlled as they have to take place in compliance with Good Manufacturing Practice (GMP). All products currently on the UK market when the Directive came into force will need to comply by 30 April 2011. No new herbal medicines can be introduced onto the UK market after 30 April 2004 unless through the Traditional Herbal Registration Scheme. This essentially means that by April 2011, herbal medicines on the UK market should be controlled for quality and safety as the European guidelines on the quality of herbal medicines apply. Companies are required to submit a registration dossier taking account of existing guidelines including Good Agricultural Practice (GACP), European Pharmacopoeia tests for pesticide residues, limits for aflatoxins, microbial limits and stability requirements. Conclusion: With the introduction of the Traditional Herbal Medicinal Products Directive and the registration scheme where the quality aspects of the product and manufacture have to take place in compliance with GMP, some of the main problems with contamination will be addressed, leading to safer herbal medicines.
Article Subject Terms: Herbal medicines; Contamination; Contaminants; Heavy metals; Aflatoxins; Fungicides; Medicinal plants; Mycotoxins; Corticoids; Mercury; Reviews; Agricultural practices; Carcinoembryonic; antigen; Pesticide residues; Pesticides; Impurities; Arsenic; Fumigants; Organic matter; guidelines; Compliance; Metals; insects; Lead; Mortality; Article Taxonomic Terms: Aristolochia; Article; Geographic Terms: British Isles; China, People's Rep.; Europe; Africa; India; X 24310 Pharmaceuticals; H 4000 Food and Drugs