Summary
Black Cohosh is a phytoestrogen alternative medicine promoted to alleviate menopausal symptoms without hormonal treatment. It is often used by women with a history of breast cancer. There is no real evidence that it is effective. There have been reports of severe liver toxicity and in 2008 Black Cohosh has been shown to increase the chance of breast cancer spreading to the lungs in mice and this research raises the question of safety.
What is Black Cohosh?
- Black Cohosh is a herb sold as a dietary supplement.
- It is used for menopausal symptoms including hot flashes.
Black Cohosh is a member of the buttercup family of plants and is native to eastern North America from Ontario south to central Georgia, and west to Missouri. It grows in woodlands. Cohosh is an indian word meaning "rough". Other common names include black snakeroot, bugwort, rattleroot, and rattleweed. Insects avoid it, which accounts for some of these names.
What are common Black Cohosh preparations?
Preparations of Black Cohosh are made from its roots and underground stems. It is classified as a phytoestrogen. Remifemin® is a commercial standardized Black Cohosh preparation which contains Black Cohosh extract equivalent to 20 mg of root per tablet.
What are the historical uses of Black Cohosh?
Black Cohosh was used by North American Indians for malaise and gynecological disorders. In 19th-century America, Black Cohosh was a home remedy used for fever, as a diuretic, and to bring on menstruation.
What clinical studies have been done on Black Cohosh and its effect on menopausal symptoms?
Black Cohosh is used primarily for hot flashes and other menopausal symptoms. A number of studies using various designs have been conducted to determine whether Black Cohosh affects menopausal symptoms but few studies were placebo controlled.
A review of all controlled trials on Black Cohosh found that the evidence does not consistently demonstrate an effect of Black Cohosh on menopausal symptoms although a beneficial effect of Black Cohosh on peri-menopausal women cannot be excluded. The efficacy of Black Cohosh as a treatment for menopausal symptoms is uncertain and further rigorous trials seem warranted.
There are some studies, however, that suggest that Black Cohosh may be effective. Compared with fluoxetine, Black Cohosh proved more effective for treating hot flushes and night sweats.0702
Others have found no benefit. For example one group concluded that Black Cohosh used in isolation, or as part of a multibotanical regimen, shows little potential as an important therapy for relief of vasomotor symptoms.0601
Black Cohosh, used alone has no effects on vaginal epithelium, endometrium, or reproductive hormones.0802
Black Cohosh does not exert an estrogenic effect on the breast.0701
In 2004, the American College of Obstetricians and Gynaecologists stated2004 "Because no large, controlled studies of Black Cohosh have yet been conducted, no recommended doses have been established, nor have specific claims been allowed regarding the herb's effectiveness. Black Cohosh does not appear to have any effect on bone density or cardiovascular health. Some researchers recommend that you limit its use to six months. The Task Force's review of studies to date has found no evidence that treatment with alternative therapies, such as Black Cohosh supplements has any significant effect on hot flashes."
How does Black Cohosh work?
How Black Cohosh works is not known. The possibility that Black Cohosh exhibits estrogenic activity has been studied but the evidence is contradictory.
Black cohosh side effects?
Black Cohosh can cause stomach discomfort and headaches.
There have been reports of damage to the liver with Black Cohosh.One patient required urgent liver transplantation for fulminant hepatic failure after the brief use of Black Cohosh.0201
Black Cohosh has been shown to increase the chance of breast cancer spreading to the lungs in mice.0803 As some women who have had breast cancer choose to take Black Cohosh to alleviate hot flushes and avoid HRT, this research raises the question safety.
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This is the personal website of David A Viniker MD FRCOG, Consultant Obstetrician and Gynaecologist at Whipps Cross University Hospital, London.
Answers to FAQs on women's health, patient information and medical advice by David A Viniker MD FRCOG, Consultant Obstetrician and Gynaecologist (Gynecologist - OBGYN), Department of Obstetrics and Gynaecology, Whipps Cross University Hospital, London
