Actaea racemosa

Native Americans used black cohosh in the belief it could treat gynecological and other disorders.[2][10][14] Following the arrival of European settlers in the U.S. who continued the use of black cohosh, the plant appeared in the U.S. Pharmacopoeia under the name "black snakeroot".[2] In the 19th century, the root was used to treat snakebite, inflamed lungs, and pain from childbirth.[15]

Extracts from the underground parts of the plant — the rhizome (Cimicifugae racemosae rhizoma) and the root (Cimicifugae racemosae radix) — are used in herbal medicine. The rhizomes and roots contain various saponins (triterpene saponins and triterpene glycosides, such as actein) as well as cimifugic acids and other phenol carboxylic acids.[3][16]

In most European countries, China, Malaysia, Thailand, Argentina and some other countries, black cohosh products are available as herbal products which have been approved by regulatory authorities ensuring reliable pharmaceutical quality, safety and efficacy for the relief of menopausal complaints such as hot flushes and profuse sweating.[3] In the U.S., India, and some other countries, black cohosh is used as a dietary supplement marketed mainly to women for treating menopausal symptoms and other gynecological problems.[10][17] Meta-analyses of contemporary evidence support these claims on menopausal complaints only for products holding a marketing authorization for this indication,[5] whereas there is no high-quality scientific evidence to support such uses for other products.[14][8][18]

The Herbal Medicinal Product Committee (HMPC) at the European Medicines Agency (EMA) has summarized the adverse drug reactions of herbal medicines made from cimicifuga with mentioning allergic skin reactions (urticaria, itching, exanthema), facial oedema and peripheral oedema, and gastrointestinal symptoms (i.e. dyspeptic disorders, diarrhoea).[3]

Studies on the long-term safety of using herbal medicines made from black cohosh are available. They do not show harmful effects on breast tissue,[19][20] endometrium,[21][22][23] or breast cancer survivors.[24] In contrast, such studies have not been published for dietary supplements made from black cohosh.[2][14][8] Most black cohosh materials are harvested from the wild. Lack of proper authentication and adulteration of commercial preparations by other plant species are risk factors in dietary supplements[10][25] and a critical matter of quality control in herbal medicinal products holding a marketing authorization. Very high doses of black cohosh may cause nausea, dizziness, visual effects, a lower heart rate, and increased perspiration.[14]

Worldwide, some 83 cases of liver damage, including hepatitis, liver failure, and elevated liver enzymes, have been associated with using black cohosh, although a cause-and-effect relationship remains undefined.[2] Millions of women have taken black cohosh without reporting adverse health effects,[8] and a meta-analysis of clinical trials found no evidence that black cohosh preparations had adverse effects on liver function.[26] Package leaflets of phytomedicines made from black cohosh caution that people with liver problems should not take it,[8][27] although a 2011 meta-analysis of research evidence suggested this concern may be unfounded.[26] In 2007, the Australian Government warned that black cohosh may cause liver damage, although rarely, and should not be used without medical supervision.[28] Other studies concluded that liver damage from use of black cohosh is unlikely.[29][30][31] The clinical picture is similar to an autoimmune hepatitis with centrilobular liver cell necrosis, which can be treated with corticosteroids.[32]

The rhizomes and roots of black cohosh (Cimicifuga racemosa rhizoma) contain diverse phytochemicals, particularly various saponins (triterpene saponins/triterpene glycosides such as actein) as well as cimifugic acids and other phenol carboxylic acids.[3][16][33][34] The pharmacologically active substance comprises the total extract.[3] In the past, estrogen-like properties were attributed to preparations from this herbal drug. However, formonetin—a phytoestrogen compound (isoflavone)—could only be detected in methanolic extracts[35] and was not found in ethanolic or isopropanolic cimicifuga extracts.[36] Today, an estrogen-like mechanism of action can be ruled out.[37][38] Regarding the alleviation of menopausal symptoms, central nervous activity was suspected as early as 2003,[39] and it has since been confirmed with preclinical and clinical data.[23][40]