Adverse Reactions to Black Cohosh

Black cohosh, an herb in the buttercup family, is widely used as a natural alternative to hormone replacement therapy. Women use black cohosh to relieve hot flashes and other symptoms of menopause. Despite being a natural herb, black cohosh is associated with side effects. The most common is stomach discomfort, but liver damage may also occur.

What is Black Cohosh

• Black cohosh, an herb native to North America, has a long history of medicinal applications dating back to Native Americans. The herb mimics the female hormone estrogen, according to the Office of Dietary Supplements (ODS) of the National Institutes of Health. Preparations made from black cohosh roots are primarily used for treating gynecological disorders such as hot flashes and other menopause symptoms, uterine and ovarian inflammation, menstrual irregularities and infertility. The herb is also used to treat kidney disorders, cough and cold, constipation, malaise, backache and neurological disorders. The American Botanical Council (ABC) claims black cohosh is the "most widely used alternative to hormone replacement therapy." Although black cohosh is a natural herb, it is still associated with adverse reactions.

Common Adverse Reactions

• The most common adverse reaction associated with black cohosh use is gastrointestinal discomfort and headaches. Other reported side effects include a heavy feeling in the legs and weight gain.

Liver Damage

• Black cohosh may cause liver damage, including hepatitis. Although liver damage associated with black cohosh use is rare, the U.S. Pharmacopeia, which is the organization that regulates drug manufacturing standards in the United States, issued an advisory. The advisory cautions people using black cohosh to stop using the herb if they see signs of liver damage (for example, jaundice, abdominal pain or dark-colored urine), according to the ODS. The ABC disputed the association between black cohosh and liver damage, stating the advisory is based on 18 anecdotal reports, of which only five were "possibly" or "probably" caused by the herb, rather than on scientific evidence.

Breast Cancer

• Because black cohosh has estrogenic properties, it may potentially cause breast tumor growth or overgrowth of the endometrium. These effects, however, have yet to be proven in long-term studies.

Drug Interactions

• The interaction of black cohosh and other medications has not been studied.

Warnings

• Black cohosh is classified as a dietary supplement, and as such it is not regulated as a drug by the U.S. Food and Drug Administration. Therefore, the concentration and quality of black cohosh varies among preparations. Long-term use of black cohosh has not been studied. The OSD recommends people with liver disorders, women with breast cancer or who are at increased risk for breast cancer and women who are pregnant avoid using black cohosh unless they are under the supervision of a health care provider.