Black cohosh is a shrub like plant native to the eastern deciduous forests of East-northeast in China. The dried root and rhizome are used medicinally. When harvested from the wild, the root is black in color. Cohosh, an Algonquin Indian word meaning "rough," refers to the plants gnarly root structure.
Native Americans valued the herb and used it for many conditions, ranging from gynecological problems to rattlesnake bites. Some 19th century American physicians used black cohosh for fever, menstrual cramps, arthritis, and insomnia. Black cohosh has been used in connection with the following conditions:
Dysmenorrhea (painful menstruation)
Black Cohosh For Hot Flashes & Menopause
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 estrogen production and increasing luteinizing hormone (LH) secretions. Hot flashes can result from these hormonal changes. Earlier animal studies and a human clinical trial suggested that black cohosh had some estrogen activity in the body and also decreased LH secretions. However, further clinical trials are needed to determine whether black cohosh has significant estrogenic actions in the body.
Small German clinical trials support the usefulness of black cohosh for women with hot flashes associated with menopause. A review of eight clinical trials found black cohosh to be both safe and effective for symptomatic relief of menopausal hot flashes. 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 flashes. While hot flashes were reduced equally at both amounts, there was no evidence of any estrogenic 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 flashes associated with menopause and is not thought to be a substitute for hormone replacement therapy in menopausal and postmenopausal women.
Below is a study done at the Department of Surgery, Mayo Clinic, Scottsdale, Arizona. Quoted directly from the study itself:
BACKGROUND: Hot flashes cause significant morbidity in postmenopausal women, including women with breast cancer. We undertook a pilot study to estimate the effectiveness of black cohosh to reduce hot flashes.
METHODS: Women who reported significant hot flashes (> or = 14 per week) were enrolled. Black cohosh was given in the form of the commercial product Remifemin. The first week was a no-treatment baseline period, and therapy was given for the subsequent 4 weeks. Hot flash data were collected by daily questionnaires during baseline and treatment weeks. Adverse effects were recorded.
RESULTS: Twenty-one women completed the study. Their mean age was 56 years (range, 38-80). Thirteen patients had a history of breast cancer. Six patients were taking tamoxifen or raloxifene. Patients reported an average of 8.3 hot flashes per day during the baseline week. The reduction in mean daily hot flash frequency was 50% (95% CI, 34%-65%), while weekly hot flash scores were reduced 56% (95% CI, 40%-71%) at completion of the study. Overall, patients reported less trouble with sleeping, less fatigue, and less abnormal sweating. No patients stopped therapy because of adverse effects.
CONCLUSIONS: Black cohosh appeared to reduce hot flashes and had a low toxicity. The efficacy found in this trial seems to be more than would be expected by a placebo effect (20%-30% hot flash reduction in previous trials). These results suggest that further evaluation of this black cohosh preparation with a phase III randomized trial is indicated.
Pockaj BA, Loprinzi CL, Sloan JA, Novotny PJ, Barton DL, Hagenmaier A, Zhang H, Lambert GH, Reeser KA, Wisbey JA.
Black Cohosh Side Effects
Black cohosh can be taken in several forms, including crude, dried root or rhizome, or as a solid, dry powdered extract. Standardized extracts of the herb are available.
Black cohosh should not be used by pregnant or breast-feeding women. Very large amounts (over several grams daily) of this herb may cause abdominal pain, nausea, headaches, and dizziness. Black cohosh is not a substitute for hormone replacement therapy during menopause.
However, Black Cohosh is found to be generally safe if taken for a limited period. From a study published at the Universities of Exeter and Plymouth:
"Black cohosh (Actaea racemosa/Cimicifuga racemosa) modern day application is the treatment of menopausal symptoms. Unlike conventional non-herbal medications, herbal preparations have not been systematically evaluated for their safety. However, the evidence from in vitro, animal and clinical studies all suggest that black cohosh is a safe herbal therapy for menopausal women if taken for a limited period. More research is needed to evaluate the safety of this herb over longer periods of time, and also to further investigate its mechanism of action."
Universities of Exeter and Plymouth, Complementary Medicine, Peninsula Medical School, 25 Victoria Park Road, Exeter, EX2 4NT, UK.