A historical, scientific and commercial perspective on the medicinal use of Pelargonium sidoides (Geraniaceae).

UNLABELLED: ETHNOPHARMACOLOGICAL CONTEXT: A detailed review of the ethnobotany and commercial history of Pelargonium sidoides is presented, together with a brief summary of pre-clinical and clinical scientific results that support the use of the plant in modern, evidence-based phytomedicines. The aim is to identify the main factors responsible for the success in product development. MATERIALS AND METHODS: The literature studied includes all modern scientific papers and also old documents and books that are no longer readily accessible. RESULTS: Available ethnobotanical information shows that several tuberous Pelargonium species (including Pelargonium sidoides) are important traditional medicines with a rich ethnobotanical history. A summary of the interesting history of the commercial development of Stevens' Cure or Umckaloabo in Europe is presented. Scientific evidence for the efficacy of the product, mainly as a treatment for acute bronchitis, is reviewed. These include numerous in vitro studies as well as 18 clinical studies. The botanical identity of the plant and its complex mixture of coumarins and other chemical constituents are summarised. CONCLUSIONS: The use of Pelargonium stems or tubers for a variety of ailments (including the complications of dysentery) is an important but hitherto under-estimated part of traditional medicine in southern Africa. Key elements in the successful development of Pelargonium sidoides from a profound traditional remedy to a highly successful phytomedicine include the choice of species, a favourable cost-benefit ratio, innovative marketing over many years, good scientific evidence of the botanical and chemical identity of the product and convincing proof of concept.