Also known as Vitex, women have used Chaste Tree Berries for thousands of years to potentially treat menstrual problems, infertility and other gynecological issues. Chaste Berry has been used for centuries to treat constipation, flatulence, and hangovers, and to induce menstruation and lactation. In modern herbal medicine, the herb is mainly used to treat breast swelling and breast pain caused by excessive secretion of the hormone prolactin during PMS or cyclic mastalgia. This herb can potentially lengthen the proliferative (first) phase of the menstrual cycle, and also might relieve water weight, headache, fatigue, and symptoms of endometriosis. Chaste Tree Berries might work by regulating and supporting the pituitary gland, which is considered the master gland for homone production.