Analysis of products suspected of containing Aristolochia or Asarum species.

Aristolochia species have been administered by those trained in traditional Chinese medicine (TCM) for centuries. After determining Aristolochia fangchi was an adulterant that caused death due to renal failure in a number of patients at a Belgian weight loss clinic, many countries took steps to regulate products containing Aristolochia fangchi as well as other Aristolochia species. The US FDA issued a Consumer Advisory 'advising consumers to stop using any products that may likely contain aristolochic acid'. The Aristolochia and Asarum genera both have been found to contain aristolochic acids. A number of websites have been found from which individuals can order products containing either Aristolochia or Asarum as an ingredient through US merchants. We purchased 25 products from such sites and analyzed them for the presence of aristolochic acid I and II by HPLC with PDA. Six of the products contained detectable amounts of I and II.