Chaste berry, also known as Vitex agnus-castus, is a shrub native to the Mediterranean and Central Asia. The fruit of the chaste berry plant has been used for centuries in traditional medicine to address a range of menstrual and reproductive disorders in women.
 
Chaste berry is believed to work by stimulating the pituitary gland to increase the production of luteinizing hormone (LH) and decrease the production of follicle-stimulating hormone (FSH). This results in a shift in the ratio of estrogen to progesterone, which can help regulate the menstrual cycle and alleviate symptoms of premenstrual syndrome (PMS) and menopause.
 
Chaste berry has also been shown to help increase fertility in some women, possibly by improving ovulation and luteal phase defects. It may also be helpful in treating certain conditions, such as acne, breast pain, and fibrocystic breast disease.
 
Chaste berry is available in various forms, including capsules, tinctures, and teas. It is generally considered safe for most people, although it may interact with certain medications and should be avoided during pregnancy. As with any supplement, it is recommended to consult with a healthcare provider before taking chaste berry.