Black Cohosh

Introduction

This fact sheet provides basic information about the herb black cohosh--common names, uses, potential side effects, and resources for more information. Black cohosh is a plant native to North America.

Common Names--black cohosh, black snakeroot, macrotys, bugbane, bugwort, rattleroot, rattleweed

Latin Names--Actaea racemosa, Cimicifuga racemosa

What It Is Used For

• Black cohosh has a history of use for rheumatism (arthritis and muscle pain), but has been used more recently to treat hot flashes, night sweats, vaginal dryness, and other symptoms that can occur during menopause.
• Black cohosh has also been used for menstrual irregularities and premenstrual syndrome, and to induce labour.

How It Is Used

The underground stems and roots of black cohosh are commonly used fresh or dried to make strong teas (infusions), capsules, solid extracts used in pills, or liquid extracts (tinctures).

What the Science Says

• Study results are mixed on whether black cohosh effectively relieves menopausal symptoms.
• Studies to date have been less than 6 months long, so long-term safety data are not currently available.
• NCCAM is funding studies to determine whether black cohosh reduces the frequency and intensity of hot flashes and other menopausal symptoms.
• There are not enough reliable data to determine whether black cohosh is effective for rheumatism or other uses.

Side Effects and Cautions

• Black cohosh can cause headaches and stomach discomfort. In clinical trials comparing the effects of the herb and those of estrogens, a low number of side effects were reported, such as headaches, gastric complaints, heaviness in the legs, and weight problems.
• No interactions have been reported between black cohosh and prescription medicines.
• Black cohosh has recently been linked to a few cases of hepatitis (inflammation of the liver), but it is not clear whether black cohosh caused the problem.
• It is not clear if black cohosh is safe for women who have had breast cancer or for pregnant women.
• Black cohosh should not be confused with blue cohosh (Caulophyllum thalictroides), which has different properties, treatment uses, and side effects than black cohosh. Black cohosh is sometimes used with blue cohosh to stimulate labour, but this therapy has caused adverse effects in newborns, which appear to be due to blue cohosh.
• It is important to inform your health care providers about any herb or dietary supplement you are using, including black cohosh. This helps to ensure safe and coordinated care.