Pueraria mirifica, also known as ‘kwao krua’ in Thai, is a plant in the genus Pueraria (family Legumiosae). It is an indigenous herb growing in deep forests of northern Thailand. The tuberous root of P. mirifica has been used in Thai folk medicine for a long time as a rejuvenating agent. In folk remedy, it was said that P. mirifica helps improve skin wrinkles and eye health, increasing energy and supporting hair growth. The root of Pueraria mirifica was reported to contain various phytoestrogens. These plant-derived chemicals mimic the biological activity of the female hormone, estrogen. Phytoestrogens reported to be found in the root of P. mirifica are miroestrol, puerarin, daidzin, daidzein, genistin, genistein, kwakhurin, and mirificin. Among them, miroestrol is thought to be responsible for the rejuvenating properties of P. mirifica. The recent scientific study demonstrated that miroestrol improved the anti-oxidant activities of superoxide dismutase and catalase.