contain any statements about possible side effects. All
herbal supplements sold in the United States must show
the scientific name of the herb on the label.
Health claims
Gingko biloba is one of the most promising tradi-
tional herbs investigated by Western medicine. The
National Center for Complementary and Alternative
Medicine (NCCAM), a government organization
within the National Institutes of Health, is sponsoring
clinical trials to determine safety and effectiveness of
gingko biloba as a treatment for more than a dozen
diseases and disorders. Individuals interested in par-
ticipating in a clinical trial at no charge can find a list
of open trials at<//www.clinicaltrials.gov>.
Some health claims for gingko biloba have
already been evaluated in large, well-controlled stud-
ies that satisfy the proof of safety and effectiveness
demanded by conventional medicine. There is good
evidence that gingko biloba can cause short-term
improvement in mental function in people with Alz-
heimer’s disease. In a well-designed study, ginkgo
biloba was as effective as the prescription drug done-
pezil (Aricept) in slowing the development of dementia
in people with mild to moderate Alzheimer’s. Ginkgo
biloba has also been shown to be effective in improv-
ing blood flow to the brain and in treating certain
other dementias. The effect of ginkgo biloba on mem-
ory in healthy young adults and in people with age-
related memory impairment is inconsistent, but strong
enough to continue to study the effects of the herb in
these populations.
In other rigorous studies, ginkgo biloba has
improved symptoms of claudication. Claudication is
leg pain that occurs during walking when insufficient
oxygen reaches the leg muscles. It is usually caused by
blocked arteries in the leg. Ginkgo biloba’s ability to
reduce blood clotting (‘‘thin the blood’’) is thought to
account for improving symptoms in people with clau-
dication. However, exercise and prescription medica-
tion were more effective in reducing leg pain due to
claudication than ginkgo biloba alone. Ginkgo biloba
has also been used, especially in Europe, to treat Ray-
naud’s disease. Raynaud’s disease causes the extrem-
ities of the body to feel cold in response to stress or
cool temperatures. During an attack of Raynaud’s
disease, the blood vessels to the affected area narrow
and blood flow is reduced.
Several health claims for ginkgo biloba center on
treating disorders of the eye, including glaucoma, age-
related macular degeneration, and type 2 diabetes-
related retinopathy. Ginkgo appears to increase
blood flow to the eye, but additional studies need to
be done to evaluate its effectiveness in helping to treat
these disorders.
The terpenoids in ginkgo biloba are thought to
help prevent nerve damage. Because of this, ginkgo
has been suggested as a treatment for tinnitus (ringing
of the ears), multiple sclerosis, cochlear deafness, and
Huntingdon’s disease. Results of studies so far are
inconsistent, and additional research is needed to
determine the usefulness of ginkgo in nerve disorders.
Some researchers have suggested that ginkgo
biloba is useful in treating depression, seasonal affective
disorder, premenstrual syndrome, altitude sickness,
vertigo (dizziness), premenstrual syndrome (PMS),
gastriccancer, side effects of anti-cancer drugs, and
pulmonary interstitial fibrosis, as well as generally
improving quality of live and sense of well being. Fur-
ther studies need to be done to evaluate these health
claims.PrecautionsGinkgo biloba seeds contain toxins that can cause
vomiting, seizures, loss of consciousness, and death,
especially in young children. Ginkgo biloba seeds are
not safe and should be avoided.
Extracts of the leaf ofGingko bilobaare generally
safe and cause few side effects when taken at recom-
mended doses for up to six months. People who are
planning to have surgery should stop taking ginkgo
biloba at least two days before their operation because
of the risk of increased bleeding. The safety of gingko
biloba in children and pregnant andbreastfeeding
women is still being studied.InteractionsGinkgo biloba has blood-thinning properties and
is likely to increase the blood-thinning and anticoagu-
lant effects of medicines such as warfarin (Coumadin),
clopidogrel (Plavix), aspirin, and nonsteroidal anti-
inflammatory drugs (e.g.Advil, Motrin). Individu-
als taking these drugs should not begin taking
ginkgo biloba without consulting their health care
provider.
Ginkgo biloba may also interact with mono-
amine-oxidase (MAO) inhibitors used to treat certain
kinds of depression and mental illness. Examples of
MAOs include isocarboxazid (Marplan), phenelzine
(Nardil) and tranylcypromine (Parnate). Individuals
taking MAOs along with ginkgo biloba may experi-
ence increased effects from the MAO.Ginkgo biloba