Topic Overview
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.
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 (such as 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.footnote 1
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.footnote 2 But other studies have
shown that black cohosh does not relieve symptoms.
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, night sweats, and sleep problems.footnote 2
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 risks like those of estrogen.
Experts do not know for sure if black cohosh causes liver
problems. But they have determined that black cohosh products should be labeled
with a statement of caution. Stop using black cohosh if you notice that you are
weak or more tired than usual, you lose your appetite, or your skin or the
whites of your eyes are yellowing. Call your doctor because these symptoms may
mean you have liver damage.footnote 3
If you plan
to take black cohosh, talk to your doctor about how to take it safely. 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.
What to avoid
Black cohosh should not be used during pregnancy or while you are breastfeeding.
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 therapy, or tamoxifen. It should not be used by
women who are allergic to aspirin.