Black Cohosh

Background

Black cohosh, a member of the buttercup family, is a plant native to North America. Native American and Chinese herbalists have traditionally used black cohosh for a variety of ailments and as an insect repellent.

Currently, people use black cohosh as a dietary supplement for hot flashes and other menopausal symptoms. It’s also been used as a dietary supplement for other conditions, including menstrual cramps and premenstrual syndrome, and to induce labor.

The part of the black cohosh plant used in herbal preparations is the root or rhizome (underground stem). Black cohosh is sold as the dried root, in tablets and capsules, and as an extract.

How Much Do We Know?

Black cohosh has been studied for menopause symptoms in people, but most of the studies were not of the highest quality. Therefore, knowledge of the effects of black cohosh is limited.

What Have We Learned?

Studies that tested black cohosh for menopause symptoms have had inconsistent results. The overall evidence is insufficient to support using black cohosh for this purpose.

There are not enough reliable data to show whether black cohosh is effective for other uses.

The National Center for Complementary and Integrative Health (NCCIH) is funding research to identify active components in black cohosh and understand their effects in the body.

What Do We Know About Safety?

In clinical trials, people have taken black cohosh for as long as 12 months with no serious harmful effects. The only reported side effects were minor problems such as upset stomach or rashes.

Some commercial black cohosh products have been found to contain the wrong herb or to contain mixtures of black cohosh and other herbs that are not listed on the label.

Cases of liver damage—some of them very serious—have been reported in people taking commercial black cohosh products. These problems are rare, and it is uncertain whether black cohosh was responsible for them. Nevertheless, people with liver disorders should consult a health care provider before taking black cohosh products, and anyone who develops symptoms of liver trouble, such as abdominal pain, dark urine, or jaundice, while taking black cohosh should stop using it and consult a health care provider.

The risk of interactions between black cohosh and medicines appears to be small. NCCIH is funding research to learn more about possible interactions involving black cohosh.

It’s not clear if black cohosh is safe for women who have had hormone-sensitive conditions such as breast cancer or for pregnant women or nursing mothers.

Black cohosh should not be confused with blue cohosh (Caulophyllum thalictroides), which has different effects and may not be safe. Black cohosh has sometimes been used with blue cohosh to stimulate labor, but this use was linked to severe adverse effects in at least one newborn.

Keep in Mind

Tell all your health care providers about any complementary or integrative health approaches you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care.

Key References

-NIH