Black cohosh is a herbaceous perennial plant native to Eastern North America. It was scientifically called Cimicifuga racemosa in the past, but it is now called Actaea racemosa due to taxonomic technicalities. It has different common names including black bugbane, black snakeroot, bugwort, rattletop, rattleweed, macrotys, and fairy candle. It belongs to the buttercup family (Ranunculaceae). Native Americans discovered that its rhizome (underground stem) and roots can be used to treat gynecological disorders, malaise, kidney disorders, rheumatism, malaria, cold, cough, constipation, backaches, sore throat, and other diseases.
Black cohosh extract is composed of different biologically active compounds including glycosides, saponins, caffeic acid, resins, isoferulic acid (with anti-inflammatory properties), and phytoestrogens (e.g. fukinolic acid). These compounds are extracted from black cohosh rhizome and roots using alcohol solvent. The extract is sold in different forms: liquid, powder, tincture, and tablets.
The mechanism of action of black cohosh is not yet clear although some researchers say that it has estrogen-like activity. Estrogen is a hormone that stimulates estrus and the development of female secondary sex characteristics. Menopause is a result of estrogen depletion in the body as a woman ages.
- Black cohosh is used to control the symptoms of menopause such as hot flashes, night sweats, vaginal dryness, heart palpitations, mood disturbances, irritability, and migraines. In early studies, black cohosh has been found to improve menopausal symptoms for up to six months. However, an opposite finding was observed in a joint study of the National Center for Complementary and Alternative Medicine (NCCAM) and the National Institute of Aging. The study concluded that black cohosh has no significant benefit in pre-menopausal and post-menopausal women. The authors, however, acknowledged that their study had few limitations like the small number of participants in each treatment group. More studies are needed to learn more about the ability of black cohosh in controlling menopausal symptoms.
- Black cohosh is used as analgesic for menstrual cramp, arthritis, and muscle pain. The analgesic effect of black cohosh can be attributed to the anti-inflammatory compounds found in it.
- Phytoestrogens found in black cohosh may help reduce bone loss, such as seen in osteoporosis. More studies are needed.
Side effects of black cohosh may include:
- Weight gain
- Slow heart rate
- Visual dimness
- Joint pains
- Abdominal pain
Black cohosh can also contain proteins that can trigger allergic reaction to human. People who are allergic to members of the buttercup family are most likely to be allergic to black cohosh. Allergy symptoms include rashes, itching, vomiting, swelling, breathing difficulty, and anaphylactic shock. People who experience these symptoms may need medical help especially those with breathing difficulty or anaphylactic shock.
Few cases of hepatitis (liver inflammation) have been reported, but direct association with the use of black cohosh has not been demonstrated. In Australia, manufacturers are required to put warning in their products stating potential harm of black cohosh to the liver. People who already have liver diseases like hepatitis and cirrhosis are advised not to use black cohosh. People should stop using black cohosh and seek medical help if they experience symptoms of liver problem such as jaundice, black urine, and abdominal pain.
Female hormones especially estrogen are linked to breast cancer development and metastasis. Since black cohosh is believed to contain phytoestrogens, women who have breast cancer or family history of breast cancer, are not advised to use black cohosh especially without doctor’s supervision. Research on the relationship of black cohosh and breast cancer is limited. More studies are needed to find out if breast cancer stimulates growth of breast cancer.
Besides breast cancer, women who have hormone-sensitive diseases like endometriosis, ovarian cancer, uterine cancer, and fibroid tumors, are not advised to use black cohosh.
Black cohosh is not recommended to pregnant women because it may stimulate contraction resulting to miscarriage or premature labor. The effect of black cohosh to breastfeeding women is unknown.
Black cohosh should not be confused to blue cohosh (Caulophyllum thalictroides), white cohosh, Cimcifuga foetida and white baneberry because they are totally different plants despite their name and physical similarities. The safety and effectiveness of these herbs have not been thoroughly studied. Black cohosh should be gathered by people who can correctly identify it to prevent gathering the wrong plant. Black cohosh “look alike” can be fatally toxic.
Black cohosh can interfere with the effectiveness of contraceptives, hormone replacement therapy, and some cancer drugs.