Chaste Tree Berry (Vitex agnus-castus). This important female herb seems to regulate the menstrual cycle of women. Its special application is for relieving the symptoms of PMS and female menopause. The unique properties of vitex are due to its pituitary-stimulating properties and its ability to increase luteinizing hormone (progesterone), which stimulates the sloughing off of the corpus luteum associated with menstruation. Vitex appears to be the single herb of choice for helping to maintain emotional balance before and during menstruation.