AbstractGarcinia mangostana L. (mangosteen, Clusiaceae) has a long history of use as a medical plant, mostly in Southeast Asia. This is a review of the phytochemistry and pharmacology of mangosteen. Traditionally mangosteen is famous for its antiinflammatory properties and is used in the treatment of skin infections and wounds. Other applications include the therapy of various conditions such as dysentery, different urinary disorders, cystitis and gonorrhoea. This review highlights the development of this botanical drug into a widely used nutraceutical. Products derived from G. mangostana are now distributed increasingly all over the world. This has given rise to a concomitant increase in research on the phytochemical constituents and biological activity of mangosteen. Central to the biological activity of the species are xanthones which are reviewed in detail. A comprehensive assessment of the biological activities of individual xanthones as well as extracts of G. mangostana is included. In addition, its potential in terms of developing novel drug leads is assessed. Products containing its fruits are now sold widely as ‘liquid botanical supplements’, but evidence for the health benefits of these products is still lacking. As shown here, a serious weakness in our knowledge is the lack of clinical data and it is not yet clear to what extent the findings about pharmacological activities are of potential clinical relevance. Copyright © 2009 John Wiley & Sons, Ltd.