The U.S. Food and Drug Administration has issued a warning for consumers to stop using dietary products that contain aristolochic acid, found primarily in a Chinese herb called Aristolochia fangchi. Consumption of products containing the botanical ingredient has been associated with permanent kidney damage; the product has also been linked to certain types of cancer, most often occurring in the urinary tract. The ingredient has been found in at least 16 products sold in the U.S., either as a single-ingredient product or as part of a supplement mixture. The products may list the ingredients "aristolochia," "bragantia," or "asarum" on the label. The FDA has issued warning labels and requests for recalls to the various manufacturers or distributors involved. Doubts about aristolochic acid first started after at least 100 individuals, all clients of one diet clinic in Belgium, developed end-stage kidney failure; additionally, a number of them were found to have some kind of kidney or bladder cancer. The Belgian Ministry of Health traced the problem to a prescription weight-loss capsule containing aristolochic acid (which had beenaccidentally added to the mixture in place of another herb). Similar cases have also been found in the United Kingdom and in France and recently, the FDA received reports of two patients in the U.S. who developed serious kidney disease associated with the use of products containing aristolochic acid. The FDA is asking healthcare professionals to report cases of kidney disease or cancers associated with the use of this product.