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Other common
name(s): black snakeroot, bugbane, bugwort,
Remifemin®;
Scientific/medical
name(s): Cimicifuga racemosa
Description
Black cohosh is a perennial woodland plant of the eastern
United States and Canada that grows from 4 to 8 feet tall and has
feathery white flowers. The root is used in herbal remedies.
Overview
Available scientific evidence does not support claims that
black cohosh is effective in treating cancer. Some studies suggest it
might interfere with some drugs used in chemotherapy. The safety of
long-term use is not known. Serious side effects are rare but have been
reported.
There is inconsistent evidence regarding whether black cohosh
is effective in relieving menopausal symptoms for women in general. Its
safety and effectiveness for women with menopausal symptoms caused by
treatment of breast cancer is also not clear.
How is it promoted for use?
Black cohosh is often referred to as a "woman's remedy"
because it is used mainly to relieve premenstrual problems, menstrual
cramps, and symptoms of menopause such as hot flashes. Commission E
(Germany's regulatory agency for herbs) has approved black cohosh for
these symptoms. Black cohosh is also a source of vitamin A and
pantothenic acid.
In the past, the helpful effects of black cohosh were thought
to be due to chemicals in the plant that resemble and mimic the effects
of the female hormone called estrogen. However, the strength of the
plant's estrogen-like effects has been disputed, and the exact way
black cohosh works in the body is not well understood.
Because some types of cancer, such as breast and endometrial
cancer, are stimulated by estrogen, some herbalists state that black
cohosh may be dangerous for people who have cancer. But another view
holds that since the herb does not actually contain estrogen, it is
safe for cancer patients. Some promoters of black cohosh state that the
herb reduces the risk of breast and prostate cancer.
Black cohosh has also been used to treat pain before, during,
and after childbirth; breast pain; ovarian pain; and uterine pain.
Other reported uses of black cohosh include arthritis pain relief,
lowering blood pressure, sedation, treatment of bronchial infections,
treatment for spasms associated with whooping cough, and treatment of
diarrhea.
What does it involve?
Black cohosh is the main ingredient in an over-the-counter
German menopausal remedy called Remifemin. In addition, black cohosh
can be found in several different forms including capsules, solutions,
tablets, tinctures, and powders. There is no standardized treatment
plan for the use of the herb. The typical dose suggested is 20 to 40
milligrams of Remifemin twice daily or 40 to 200 milligrams of dried
root powder.
What is the history behind it?
Cohosh is a Native American word that means "knobby rough
roots," which describes the appearance of the plant's roots. Native
Americans used black cohosh to treat uterine disorders such as
menstrual and menopausal symptoms, as well as other ailments, such as
diarrhea, sore throat, arthritis, and general weakness. The herb has
been approved in Germany for the same purposes for more than 50 years
and is commonly prescribed in other European countries.
What is the evidence?
There is inconsistent evidence of effectiveness from clinical
trials. Some studies report that black cohosh relieves menopausal
symptoms while others do not. Some of the disagreement may be due to
differences in the herbal products tested. A 2005 study of 304 women
found that, compared to a placebo, black cohosh helped symptoms of
menopause. It seemed more effective for women whose symptoms had begun
recently than for those who had been postmenopausal for a longer time.
On the other hand, a 2006 study of 351 women found that menopausal
symptoms were helped by hormone therapy but not by black cohosh (either
alone or with other herbs). Clinical trial results published in 2008
reported no difference between black cohosh and placebo regarding
vaginal dryness, menstrual irregularity, female hormones, or the
structure of vaginal cells in Pap test samples. The North American
Menopause Society recommends considering black cohosh as one of the
nonprescription remedies for mild menopausal symptoms, but points out
that the safety of this herb for women with breast cancer remains
uncertain.
In a smaller study of 21 women, 13 of whom had breast cancer,
participants also reported less trouble with sleeping, less fatigue,
and less abnormal sweating after they started taking black cohosh,
although this study did not use a placebo control group. This means
that it was impossible to conclude whether the results were due to
black cohosh and not a placebo effect.
A 2001 study of black cohosh and an inactive placebo for
breast cancer survivors found no difference in severity or number of
hot flashes, although there was a slight reduction in sweating. About
two-thirds of these patients were also taking tamoxifen, an
anti-estrogen drug that is commonly used in the treatment of breast
cancer. Two years later, another study of women with breast cancer
being treated with tamoxifen found that hot flashes were less severe
and occurred less often in women taking black cohosh. However, a 2006
study of 132 cancer survivors found no effect on hot flashes.
Are there any possible problems or
complications?
This product is sold as a
dietary supplement in the United
States. Unlike drugs (which must be tested before being allowed to be
sold), the companies that make supplements are not required to prove to
the Food and Drug Administration that their supplements are safe or
effective, as long as they don't claim the supplements can prevent,
treat, or cure any specific disease.
Some such products may not
contain the amount of the herb or
substance that is written on the label, and some may include other
substances (contaminants). Actual amounts per dose may vary between
brands or even between different batches of the same brand.
Most such
supplements have not been tested to find out if they
interact with medicines, foods, or other herbs and supplements. Even
though some reports of interactions and harmful effects may be
published, full studies of interactions and effects are not often
available. Because of these limitations, any information on ill effects
and interactions below should be considered incomplete.
Serious reactions to moderate doses of black cohosh are very
uncommon. Common side effects include upset stomach, nausea, and
vomiting. A very high dose may cause slow heart rate, uterine cramps,
headache, dizziness, tremors, joint pain, and light-headedness. There
have been a few reports of serious liver disease among women who had
recently started using black cohosh. For this reason, some doctors
suggest that people who already have liver problems should not use this
supplement.
Some doctors are concerned that taking black cohosh might
affect how conventional cancer treatments work. There are conflicting
results among studies of cancer cells grown in laboratory dishes. Black
cohosh does not seem to have an impact on the effectiveness of
radiation therapy in these cells, while the herb seems to make some
chemotherapy drugs less effective and others more effective. Some
studies found black cohosh may reduce the growth of breast cancer cells
in laboratory dishes, but another study suggested that it can increase
the spread of breast cancer in mice. Because of these conflicting
reports, until more is known about this issue, many oncologists
recommend a cautious approach and suggest delaying use of black cohosh
until treatment is over.
Allergic reactions are possible but rarely reported. Those who
are allergic to other members of the buttercup family may be more
likely to react to black cohosh. The herb also contains small amounts
of salicylic acid and should be used with caution by those allergic to
aspirin.
Commission E (Germany’s regulatory agency for herbs)
recommends that the herb not be taken for more than 6 months in a row.
It should be used with caution in people with high blood pressure and
those taking medication for high blood pressure. Women who are thinking
about any form of hormone replacement therapy should consult their
doctors before taking black cohosh. Women who are pregnant or
breast-feeding should not use this herb. Relying on this type of
treatment alone and avoiding or delaying conventional medical care for
cancer may have serious health consequences.
Additional Resources
More information from your American Cancer
Society
The following information on complementary and alternative
therapies may also be helpful to you. These materials may be found on
our Web site (www.cancer.org)
or ordered from our toll-free number (1-800-ACS-2345).
References
Black cohosh. Memorial Sloan-Kettering Cancer Center Web site.
http://www.mskcc.org/mskcc/html/69140.cfm. Accessed April 6, 2007.
Blumenthal M, ed. The Complete German Commission E Monographs:
Therapeutic Guide to Herbal Medicines. Austin, TX: American Botanical
Council; 1998.
Cohen SM, O'Connor AM, Hart J, Merel NH, Te HS. Autoimmune
hepatitis associated with the use of black cohosh: a case study.
Menopause.
2004;11:575-577.
Davis V, et al. Effects of black cohosh on mammary tumor
development and progression in MMTV-neu transgenic mice. Abstract
Number R1 90. Proceedings
of the American Association of Cancer
Research, Vol 44, 2nd ed., July 2003.
Hernández Muñoz G, Pluchino S.
Cimicifuga racemosa for the treatment of hot flushes in women surviving
breast cancer. Maturitas.
2003;44 Suppl 1:S59-S65.
Jacobson JS, Troxel AB, Evans J, Klaus L, Vahdat L, Kinne D,
Lo KM, Moore A, Rosenman PJ, Kaufman EL, Neugut AI, Grann VR.
Randomized trial of black cohosh for the treatment of hot flashes among
women with a history of breast cancer. J Clin Oncol.
2001;19:2739-2745.
Low Dog T, Powell KL, Weisman SM. Critical evaluation of the
safety of Cimicifuga racemosa in menopause symptom relief. Menopause.
2003;10:299-313.
Lynch CR, Folkers ME, Hutson WR. Fulminant hepatic failure
associated with the use of black cohosh: a case report. Liver Transpl.
2006;12:989-992.
Natural Standard. Herbal/plant therapies: black cohosh
(cimicifuga racemosa [l.] nutt.) Complementary/Integrative Medicine
Education Resources, The University of Texas M.D. Anderson Cancer
Center Web site.
http://www.mdanderson.org/departments/cimer/display.cfm?id=454642F6-FA6F-4259-9CC981E93779D461&method=displayFull.
Accessed June 4, 2008.
Neff MJ. NAMS releases position statement on the treatment of
vasomotor symptoms associated with menopause. Am Fam Physician.
2004;70:393-394, 396, 399.
Newton KM, Reed SD, LaCroix AZ, Grothaus LC, Ehrlich K,
Guiltinan J. Treatment of vasomotor symptoms of menopause with black
cohosh, multibotanicals, soy, hormone therapy, or placebo: a randomized
trial. Ann Intern Med. 2006;145:869-879.
Summary for patients in: Ann
Intern Med. 2006;145:I25.
North American Menopause Society. Treatment of
menopause-associated vasomotor symptoms: position statement of The
North American Menopause Society. Menopause.
2004;11:11-33.
Osmers R, Friede M, Liske E, Schnitker J, Freudenstein J,
Henneicke-von Zepelin HH. Efficacy and safety of isopropanolic black
cohosh extract for climacteric symptoms. Obstet Gynecol.
2005;105:1074-1083.
Pockaj BA, Gallagher JG, Loprinzi CL, Stella PJ, Barton DL,
Sloan JA, Lavasseur BI, Rao RM, Fitch TR, Rowland KM, Novotny PJ, Flynn
PJ, Richelson E, Fauq AH. Phase III double-blind, randomized,
placebo-controlled crossover trial of black cohosh in the management of
hot flashes: NCCTG Trial N01CC1. J
Clin Oncol. 2006;24:2836-2841.
Pockaj BA, Loprinzi CL, Sloan JA, Novotny PJ, Barton DL,
Hagenmaier A, Zhang H, Lambert GH, Reeser KA, Wisbey JA. Pilot
evaluation of black cohosh for the treatment of hot flashes in women.
Cancer Invest.
2004;22:515-521.
Reed SD, Newton KM, LaCroix AZ, Grothaus LC, Grieco VS,
Ehrlich K. Vaginal, endometrial, and reproductive hormone findings:
randomized, placebo-controlled trial of black cohosh, multibotanical
herbs, and dietary soy for vasomotor symptoms: the Herbal Alternatives
for Menopause (HALT) Study. Menopause.
2008;15:51–58.
Rockwell S, Liu Y, Higgins SA. Alteration of the effects of
cancer therapy agents on breast cancer cells by the herbal medicine
black cohosh. Breast
Cancer Res Treat. 2005;90:233-239.
Stoll W, et al. Phytopharmacon influences atrophic vaginal
epithelium. Double-blind study of Cimicifuga vs. estrogenic substances
[in German]. Therapeutikon.
1987;1:23-31.
Wuttke W, Seidlová-Wuttke D, Gorkow C. The
Cimicifuga preparation BNO 1055 vs conjugated estrogens in a
double-blind placebo-controlled study: effects on menopause symptoms
and bone markers. Maturitas.
2003;44 Suppl 1:S67-S77.
Note: This information may not cover
all possible claims, uses, actions, precautions, side effects or
interactions. It is not intended as medical advice, and should not be
relied upon as a substitute for consultation with your doctor, who is
familiar with your medical situation.
Last Medical Review: 11/01/2008
Last Revised: 11/01/2008
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