There has been a veritable explosion of interest in phytoestrogens, a family of plant-derived compounds with weak estrogenic and antiestrogenic proprieties, and in particular in the potential health-benefits that a rich diet in these compounds might confer on many hormone-related diseases. Phytoestrogens compounds include isoflavones, other phenolic structures, lignans, coumestans and resorcylic acid lactones. Much of the current interest in the pharmacology and physiology of these bioactive phytochemicals has focused on the class of isoflavones. These phenolic compounds possess in addition to estrogenic activity, a myriad of biological properties that can impact on many biochemical and physiological processes. This review focuses on recent studies pertinent to this field and includes the chemistry, dietary sources, pharmacology, and potential therapeutic use of isoflavones class and also the risks and safety of isoflavones consumption.