Healthnotes Newswire (January 25, 2001)—According to a clinical trial published in this week’s edition of BMJ, the journal of the British Medical Association, an herbal extract from the berry of the chaste tree (Vitex agnus castus) safely and effectively reduces symptoms of premenstrual syndrome (PMS).¹

Coordinated by researchers at the Institute for Health Care and Science in Hüttenberg, Germany, the trial evaluated 170 women (average age 36 years) with PMS, who were assigned to take either a tablet containing a concentrated extract of chaste tree berry (20 mg) or a placebo tablet once daily for three consecutive menstrual cycles. Women were asked to rate changes in PMS symptoms, such as irritability, mood changes, anger, headache, breast tenderness, and bloating.

At the end of the trial, women taking the herbal extract reported a 52% overall reduction in PMS symptoms compared with only 24% for those taking placebo. Women taking the chaste tree extract reported significantly greater reductions in irritability, mood changes, anger, headache, and breast tenderness than did women taking placebo. The only symptom that didn’t seem to change significantly in the herbal group was bloating before their period.

Reports of side effects were rare in both groups. Four women out of 86 taking the chaste tree berry extract reported mild side effects, such as acne, skin rash, and bleeding between their periods. None of these symptoms led to women dropping out of the study.

How does it work?

A condition known as “luteal phase defect” occurs in some women who produce sufficient estrogen during the first part of their cycle, but too little progesterone during the second phase (luteal phase) of their cycle. This results in a shortening of their normal cycle and can lead to PMS and even to an absence of menstruation in some cases (also known as amenorrhea).² Chaste tree berry extracts help reinstate normal balance between estrogen and progesterone during the luteal phase of the menstrual cycle.³

Breast tenderness and pain associated with a woman’s period can often be traced to the overproduction of the hormone prolactin. Produced by the pituitary gland, prolactin is necessary for nursing mothers to produce breast milk. Clinical trials have shown chaste tree berry extract to keep the overproduction of the hormone in check⁴ and to effectively reduce breast pain associated with a woman’s period.⁵

While earlier, uncontrolled trials^{6 7} and a comparison study with vitamin B6⁸ have suggested chaste tree berry’s usefulness in managing symptoms of PMS, the new trial is the first placebo-controlled trial to clearly demonstrate the herb’s effectiveness in treating PMS. Dr. Rued Schellenberg, the lead researcher on the trial, states that chaste tree berry extract is “…an effective and well-tolerated treatment for the relief of symptoms of premenstrual syndrome.” He adds, “This herbal remedy ought to be considered a therapeutic option in women in whom a causal origin for this syndrome cannot be established.” As the discovery of a primary cause of PMS is rare in most women, this trial should lead to wider recognition of chaste tree berry extract as a promising treatment for PMS sufferers.

Native to valleys and riverbanks of the Mediterranean and central Asia, chaste tree (also called vitex) is a shrub that produces dark brown to black fruit the size of a peppercorn. Preparations of the fruit have been approved by German health authorities for the treatment of menstrual irregularities, such as PMS and breast pain associated with a woman’s period.⁹ Chaste tree berry extracts do not contain hormones but should not be used together with birth control pills or other hormone replacement therapies without the guidance of a healthcare professional. Chaste tree berry extract should not be used during pregnancy.