Phyto-oestrogens or phytoestrogens are naturally occurring oestrogens derived from plants. They have a similar action to oestrogens produced by the human body, although the concentration of oestrogen in plant sources is very low. Phyto-oestrogens are used to treat symptoms of  menopause, although there is not yet enough evidence to determine whether or not they effectively relieve menopausal symptoms.