Vitex agnus-castus, otherwise known as chaste tree, has a long history in Western herbal  medicine.

Hippocrates reported Its effect on female  reproduction and fertility.

In the Middle Ages, monks  used chaste tree to decrease their sexual desire (hence the common  names). In recent years, research has shown that the  shrubs small fruit is an effective treatment for premenstrual  syndrome and infertility.

The German Commission E  approved chaste tree for menstrual cycle irregularity,  premenstrual syndrome (PMS), and mastodynia (breast  pain). (The German Commission E Is a committee set up by  the German government in 1978, consisting of scientists,  toxicologists, pharmacists, and doctors, to review safety  and efficacy of herbs sold in that country.)

Human and  animal research shows that constituents in the herb bind to dopamine, receptors in the anterior pituitary and decrease  both basal- and thyrotropin-releasJng-hormone-stimulated  secretion of prolactin. This decrease in prolactin leads to  increased progesterone production in the luteal phase of  the menstrual cycle, which reduces symptoms of PMS.

German researchers have performed several studies on  Vitex and PMS.

In a randomized, doubie-blind, placebocontrolled  study, 170 women with PMS (mean age 36 years)  were followed over three menstrual cycles.

Eighty-six ofthe  women received one 20 mg dry chaste tree extract tablet  each day, and the other 84 took a matching placebo.

In the  extract group, 52% ofthe women had at least 507o reduction  of PMS symptoms at the end of three cycles. Four in this  group reported mild adverse events (details unreported).

In  comparison, 24% of the placebo group reported a 507o or  more reduction of PMS symptoms with three mild adverse  reactions.