Black cohosh, also known as black snakeroot or bugbane, is
a medicinal root. It is used to treat women's hormone-related symptoms,
including
premenstrual syndrome (PMS), menstrual cramps, and
menopausal symptoms.
Black cohosh
contains potent
phytochemicals that have an effect on the
endocrine system. How it works is not yet
clear.1
Black cohosh is widely used in
the United States, Australia, and Germany. The German government has approved
it as a prescription alternative to
hormone therapy. In the U.S., black cohosh is
available without a prescription. Be sure to talk to your doctor before you
take it.
You can buy black cohosh as a standardized extract in
20 mg pill form (Remifemin), which is taken
twice a day. Root, extract, and tincture forms are also available in health
food stores.
When black cohosh is used at regular doses, its only
known side effect is occasional stomach discomfort.2
But black cohosh may have risks that are not yet known, including possible
effects on liver function. More research needs to be done before experts can
recommend it for long-term use.
Is it effective?
Studies on black cohosh have had
mixed results. Some studies have shown that black cohosh can relieve menopause
symptoms such as hot flashes.3 But other studies have
shown that black cohosh does not relieve symptoms.4
These mixed results may mean that black cohosh
can relieve symptoms in some women, but does not relieve symptoms in others.
Or, the different results may be because different preparations were used in
the studies.
In the studies where black cohosh relieved symptoms,
it reduced
hot flashes, profuse sweating, mood swings,
irritability, depressive mood, heart palpitations, sleep problems, headache,
and vertigo related to perimenopause.3, 5, 6
Is it safe?
Large, long-term studies have not yet
been done to confirm whether long-term use of black cohosh is safe. Because
black cohosh has benefits somewhat like
estrogen therapy, it may also have some estrogen-like
risks.
If you plan to take black cohosh, talk to your doctor
about how to take it safely.7 You may be able to take
it short-term (no more than 6 months), or possibly longer but with regular
checkups to look for estrogen-related changes in the uterus and breasts.
Estrogen may increase the risk of cancer in women who have a
history of uterine cancer or breast cancer or who are at high risk for breast
cancer. Since black cohosh may work in ways similar to estrogen, these
high-risk women should avoid using black cohosh until more is known about the
long-term risks.
As with any medicine, be careful to avoid
overdosing with black cohosh. Symptoms of overdose include vertigo, headache,
nausea, vomiting, impaired vision, and impaired circulation. None of these
symptoms have been reported with regular doses of black cohosh.6
What to avoid
Black cohosh should not be used during pregnancy or while you are breast-feeding.
Do not take black cohosh if there is any chance that you might be
pregnant.
Black cohosh should not be combined with birth control
pills, hormone replacement therapy, or tamoxifen. It should not be used by
women who are allergic to aspirin.