Herbs & Supplements

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Uses

Note: Black cohosh is different from both blue cohosh and white cohosh. Blue cohosh is frequently used in combination with black cohosh, but the effects of the two products are very different. White cohosh, also called white baneberry, is poisonous. It should never be taken by mouth. Individuals who have any doubts about the origin of a cohosh product should not use it.

Because premenopausal women have fewer heart problems than men of similar ages, the female hormones estrogen and progestin were thought to protect against heart disease. Therefore, hormone replacement therapy (HRT) drugs were prescribed widely for postmenopausal women. However, two recent large clinical trials--the Women's Health Initiative (WHI) and the Heart Estrogen/progestin Replacement Study (HERS)--showed that supplemental HRT is not heart protective. In fact, it increased risks of heart disease, breast cancer, and stroke for some women.

Interest has been renewed in the use of black cohosh and other "natural" alternatives for female HRT. Although black cohosh was long thought to contain chemicals that act like estrogen in the body, results of recent clinical studies have found that it not only has little or no estrogenic activity, but that it actually blocks estrogen. Still, black cohosh is used mostly to treat complaints such as premenstrual syndrome (PMS), hormone-related migraines, and menopausal symptoms. For many women, it is at least mildly effective in relieving bloating, breast soreness, cramps, emotional changes, swelling, and other menstrual or menopausal problems. However, in clinical studies, black cohosh generally has not relieved treatment-related symptoms such as hot flashes for women who previously had breast cancer.

Studies in animals suggest that black cohosh may also have other beneficial effects. It may help slow or prevent osteoporosis, for example. A few studies that were done in the 1960s and 1970s found black cohosh to have a blood-pressure lowering effect in laboratory animals. Black cohosh also seems to be a mild sedative, which may relieve anxiety or encourage sleep. However, few human studies have been conducted to verify these results. Currently, the Office of Dietary Supplements, a division of the U.S. National Institutes of Health, is sponsoring clinical trials to test the usefulness of black cohosh for treating several conditions.