Vitex agnus castus, also known as vitex, chaste tree, chasteberry, Abraham’s balm, lilac chaste tree, monk’s pepper, or agnus castus, is a flowering plant in the Lamiaceae family. Native to the Mediterranean region, agnus castus is used to treat a variety of health problems including premenstrual syndrome (PMS), infertility, menstrual disorders, and issues associated with menopause.