[Herbal remedies: nephrotoxicity and drug interactions]

The first reports of interstitial fibrosis leading to rapidly progressing chronic renal failure (CRF) in young women undergoing slimming treatment appeared at the beginning of the 1990s in Belgium. These slimming pills erroneously contained powdered roots of plants - picked in China - belonging to the Aristolochia instead of Stephania tetranda family. In the following years, after new cases had occurred worldwide, the term aristolochic acid nephropathy (AAN) came into use. Despite numerous warnings from various post-marketing surveillance institutes, products containing aristolochic acid are still widely used by Asiatic herbal practitioners and easily available on the Internet, where they are marketed without being subject to any regulations. In 2002 the IARC (International Agency for Research on Cancer) conclusively recognized the urothelial carcinogenicity of aristolochic acid. Because of the globalization and the growing use of phytotherapy worldwide, nephrologists should take into account AAN as a possible cause of CRF. In addition to assessing the direct kidney toxicity caused by some products used in phytotherapy, the authors conclude that it is necessary to research more closely possible drug interactions and side effects of commonly used herbs such as Echinacea, Gingko biloba, St. John's wort, ginseng, and garlic, which patients consider to be natural, non-toxic and self-prescribed remedies and whose use they therefore seldom disclose to their doctors.