Black Cohosh

Botanical name: Cimicifuga racemosa

Parts used and where grown

Black cohosh is a shrub-like plant native to the eastern deciduous forests of North America, ranging from southern Ontario to Georgia, north to Wisconsin and west to Arkansas. The dried root and rhizome are used medicinally.¹ When harvested from the wild, the root is black in colour. Cohosh, an Algonquin Indian word meaning “rough,” refers to the plants gnarly root structure.²

Black cohosh has been used in connection with the following conditions (refer to the individual health concern for complete information):

Science Ratings

Health Concerns

Menopause

Dysmenorrhoea (painful menstruation)

Osteoporosis

Premenstrual syndrome

Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars

Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star

For a herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

Historical or traditional use (may or may not be supported by scientific studies)

Native Americans valued the herb and used it for many conditions, ranging from gynaecological problems to rattlesnake bites. Some 19th century American physicians used black cohosh for fever, menstrual cramps, arthritis, and insomnia.³

Active constituents

Black cohosh contains several ingredients, including triterpene glycosides (e.g., acetin and 27-deoxyactein) and isoflavones (e.g., formononetin). Other constituents include aromatic acids, tannins, resins, fatty acids, starches, and sugars. As a woman approaches menopause, the signals between the ovaries and pituitary gland diminish, slowing down oestrogen production and increasing luteinizing hormone (LH) secretions. Hot flushes can result from these hormonal changes. Earlier animal studies⁴ ⁵ and a human clinical trial⁶ suggested that black cohosh had some oestrogen activity in the body and also decreased LH secretions. However, more recent animal studies⁷ and a clinical trial⁸ have found no oestrogen activity for black cohosh extracts. Further clinical trials are needed to determine whether black cohosh has significant oestrogenic actions in the body.

Small German clinical trials support the usefulness of black cohosh for women with hot flushes associated with menopause.⁹ ¹⁰ A review of eight clinical trials found black cohosh to be both safe and effective for symptomatic relief of menopausal hot flushes.¹¹ Other symptoms which improved included night sweats, insomnia, nervousness, and irritability. A clinical trial compared the effects of 40 mg versus 130 mg of black cohosh in menopausal women with complaints of hot flushes.¹² While hot flushes were reduced equally at both amounts, there was no evidence of any oestrogenic effect in any of the women. Although further trials are needed, this trial suggests that black cohosh is best reserved only for the symptomatic treatment of hot flushes associated with menopause and is not thought to be a substitute for hormone replacement therapy in menopausal and postmenopausal women.

A recent study suggests black cohosh may protect animals from osteoporosis.¹³ Human studies have not confirmed this action.

How much is usually taken?

Black cohosh can be taken in several forms, including crude, dried root or rhizome (300–2,000 mg per day), or as a solid, dry powdered extract (250 mg three times per day). Standardised extracts of the herb are available. The recommended amount is 20–40 mg twice per day.¹⁴ The best researched extract provides 1 mg of deoxyactein per 20 mg of extract. Tinctures can be taken at 2–4 ml three times per day.¹⁵ Black cohosh can be taken for up to six months, and then it should be discontinued.¹⁶

Are there any side effects or interactions?

Black cohosh should not be used by pregnant or breast-feeding women.¹⁷ Very large amounts (over several grams daily) of this herb may cause abdominal pain, nausea, headaches, and dizziness.

There is one case report of a woman developing auto-immune hepatitis while using black cohosh.¹⁸ A cause–effect relationship is in doubt, however, because the hepatitis did not resolve after black cohosh was discontinued. A few cases have also been reported in which severe liver failure was attributed to the use of black cohosh.¹⁹ While a cause–effect relationship is difficult to prove, and while such a side effect appears to be rare, people taking black cohosh should be alert to signs of possible liver disease, such as nausea, loss of appetite, fatigue, and tan-colored urine. Black cohosh is not a substitute for hormone replacement therapy during menopause.

At the time of writing, there were no well-known drug interactions with black cohosh.

References
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1. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics, 2d ed. New York: John Wiley & Sons, 1996, 88–9.

2. Castleman M. The Healing Herbs. Emmaus, PA: Rodale Press, 1991, 75–8.

3. Foster S. Herbs for Your Health. Loveland, CO: Interweave Press, 1996, 12–3.

4. Jarry H, Harnischfeger G, Düker E. Studies on endocrine effects of the contents of Cimicifuga racemosa. 2. In vitro binding of compounds to estrogen receptors. Planta Medica 1985;51:316–9.

5. Jarry H, Harnischfeger G. Studies on endocrine effects of the contents of Cimicifuga racemosa. 1. Influence on the serum concentration of pituitary hormones in ovariectomized rats. Planta Medica 1985;51:46–9.

6. Düker EM, Kopanski L, Jarry H, Wuttke W. Effects of extracts from Cimicifuga racemosa on gonadotropin release in menopausal women and ovariectomized rats. Planta Medica 1991;57:420–4.

7. Einer-Jensen N, Zhao J, Andersen KP, Kristoffersen K. Cimicifuga and Melbrosia lack estrogenic effects in mice and rats. Maturitas 1996;25:149–53.

8. Liske E, Wüstenberg P, Boblitz N. Human pharmacological investigations during treatment of climacteric complaints with Cimicifuga racemosa (Remifemin®): No estrogen-like effects [Poster presentation]. 2nd International Congress on Phytomedicine, London, October 15–16, 1998.

9. Stoll W. Phytopharmaceutical influences atrophic vaginal epithelium. Double-blind study on Cimicifuga versus an estrogen preparation. Therapeutikon 1987;1:23–32.

10. Warnecke G. Using phyto-treatment to influence menopause symptoms. Med Welt 1985;36:871–4.

11. Düker EM, Kopanski L, Jarry H, Wuttke W. Effects of extracts from Cimicifuga racemosa on gonadotropin release in menopausal women and ovariectomized rats. Planta Medica 1991;57:420–4.

12. Liske E, Wüstenberg P. Therapy of climacteric complaints with Cimicifuga racemosa: a herbal medicine with clinically proven evidence [Abstract #98.0020]. Poster Presentation, 9th Annual Meeting of the North American Menopause Society, Toronto, Canada, September 16–9, 1998.

13. Kadota S, Li JX, Litt Y, et al. Effects of cimicifugae rhizome on serum calcium and phosphate levels in low calcium dietary rats and on bone mineral density in ovariectomized rats. Phytomed 1996/7;3:379–85.

14. Murray MT. The Healing Power of Herbs. Rocklin, CA: Prima Publishing, 1995, 376.

15. Bradley PR, ed. British Herbal Compendium, vol 1. Bournemouth, Dorset, UK: British Herbal Medicine Association, 1992, 34–6.

16. Blumenthal M, Busse WR, Goldberg A, et al. (eds). The Complete Commission E Monographs: Therapeutic Guide to Herbal Medicines. Boston, MA: Integrative Medicine Communications, 1998, 90.

17. Gruenwald J. Standardized black cohosh (Cimicifuga) extract clinical monograph. Quart Rev Nat Med 1998;Summer:117–25.

18. Cohen SM, O'Connor AM, Hart J, et al. Autoimmune hepatitis associated with the use of black cohosh: a case study. Menopause 2004;11:575–7.

19. Levitsky J, Alli TA, Wisecarver J, Sorrell MF. Fulminant liver failure associated with the use of black cohosh. Dig Dis Sci 2005;50:538–9.

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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or chemist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires March 2007.