Premenstrual syndrome (PMS) is a cluster of physical and emotional symptoms associated with the menstrual cycle. Most women experience some degree of PMS at some point in their menstrual history, although symptoms vary significantly from woman to woman. Reproductive hormones and neurotransmitters are thought to play a central role in the etiology of PMS. Five to ten days prior to menses, plasma estrogens rise and progesterone levels decline. These changes are accompanied by an increase in follicle stimulating hormone (FSH) six to nine days prior to menstruation, and peak aldosterone levels two to eight days before menstruation. Prolactin levels are elevated in most PMS patients. Other biochemical pathways such as the insulin response, and uptake of vitamins and minerals are being studied as potential causative factors. One hypothesis suggests that PMS may be due to an aberration in blood viscosity and red blood cell hydration during the menstrual cycle.

St. John’s wort has received attention for its potential ability to treat mild to moderate depression. It has been used extensively by physicians in Europe as the agent of choice for mild or moderate depression. With approximately 18 million Americans experiencing depression in a given year from a variety of causes, St. John's wort is attracting attention as a safe and natural alternative to current prescription therapies. Scientists think that two compounds, hypericin and hyperforin, give St. John's wort its ability to support moods and counteract feelings of depression. Scientists believe that these compounds may inhibit the breakdown of several neurotransmitters, including serotonin, which is partially responsible for controlling moods and emotions.

The chasteberry tree finds its origins in the Mediterranean. Its fruit is harvested and dried for medicinal purposes. It has a long folk history of use in women's health. Chasteberry (commonly know as vitex) has been recommended for use in mild to moderate complaints, especially in endometriosis, menopause, and PMS symptoms.
Researchers from the Royal Melbourne Institute of Technology University, Victoria, Australia conducted a study to determine the effect St. John’s wort and chasteberry would have on PMS symptoms. The double-blind, randomized, placebo-controlled trial took place for 16 weeks involving fourteen perimenopausal women. PMS scores were measured on the Abrahams Menstrual Symptoms Questionaire. The herbal combination or placebo tablets were administered two times a day. The results were the herbal combination treatment was superior to the placebo for total PMS scores. In conclusion the researchers suggested that there is a potential clinical application for the herbal combination in treating PMS symptoms among perimenopausal women.¹

¹ van Die MD, Bone KM, Burger HG, et al. Effects of a combination of Hypericum perforatum and Vitex agnus-castus on PMS-like symptoms in late-perimenopausal women: findings from a subpopulation analysis. J Altern Complement Med. 2009;15(9):1045-8.