Black Cohosh

Traditionally used by Native Americans as a treatment for fatigue, snakebites and arthritis, black cohosh has garnered much attention in recent years for reducing the aggravating symptoms associated with menopause, including hot flashes, sweating, headache, nervousness, irritability, sleep disturbance, anxiety, vaginal dryness, and depression.

How It Works

Although its ability to alleviate the symptoms of menopause is clear, black cohosh's exact mechanism of action is not. Many researchers believe the herb may act much like a phytoestrogen - a plant that produces effects similar to estrogen - by binding with estrogen receptor sites. However, two recent studies question black cohosh's classification as a phytoestrogen. In one study, when two different dosages of black cohosh were administered, researchers found that although hot flashes were not as frequent or severe, black cohosh did not exhibit an estrogen-like effect once in the body. So, just how black cohosh works has yet to be determined.

What It Might Do for You

In addition to relieving hot flashes and symptoms associated with menopause, black cohosh also holds some promise in treating premenstrual discomfort and painful periods.

Potential Side Effects

Black cohosh seldom produces any side effects other than occasional mild gastrointestinal distress. Unlike estrogen, black cohosh does not appear to stimulate breast-cancer cell growth. However, black cohosh has not been studied as extensively as estrogen. For this reason, black cohosh may not be safe for those with a past medical history of breast cancer.

Herb-Drug Interactions

No drug interactions have been reported. But, before you self-treat any menopausal or premenstrual symptom, check with your health care provider to see if black cohosh is right for you - especially if you are on hormone replacement therapy as the two may be incompatible. Also, keep in mind that black cohosh is not a substitute for hormone replacement therapy.

Principal Author:

Stefanie Perelman, M.S., R.D., holds a B.A. in journalism from the University of Wisconsin-Madison and a master's in clinical dietetics from New York University. A registered dietitian, she presently works at Montefiore Medical Center in the Bronx and is available for private consultation.

Nutrition Editor

Donna Tinnerello MS, RD, CD/N is registered dietitian with more than 10 years experience in HIV and nutrition. She works in lower Manhattan at Cabrini Medical Center, the community and in private practice. Her subspecialties are cardiovascular, renal, gastrointestinal disease, diabetes and weight loss. Donna is available for private consultation by referral only.