ginkgo tree (commonly planted for ornamental purposes). The leaves contain numerous biologically active substances, such as ginkgolides and flavonoids. Ginkgo is one of the most commonly used herbal supplements.
The fruit of the ginkgo tree is not used in ginkgo products because of its bad smell. Contact with the fruit pulp, which may be encountered under female ginkgo trees, can cause severe skin inflammation (dermatitis). The seeds of the fruit are toxic and can cause seizures and, in large amounts, death. Sometimes less expensive ingredients (eg, rutin, quercetin) are added to gingko preparations.
(See also Overview of Dietary Supplements.)
Claims for Ginkgo
Ginkgo reduces the clotting tendency of particles in the blood that help stop bleeding (platelets), dilates blood vessels (thereby improving blood flow), and reduces inflammation. People take ginkgo for many reasons, such as improving blood flow to the lower legs when there is atherosclerotic vascular disease of the arteries in the legs (peripheral arterial disease); treating dementia (as in Alzheimer disease), type 2 diabetes, age-related macular degeneration (an eye disease), ringing in the ears (tinnitus), and altitude sickness
Evidence for Ginkgo
Scientific studies show ginkgo benefits people with peripheral arterial disease, although the benefit is minor. Ginkgo increased the distance that affected people could walk without pain.
Meaningful benefits for people with dementia seem unlikely based on findings from a large clinical trial. In this clinical trial, ginkgo was not effective in reducing the development of dementia and Alzheimer disease in older people. However, other studies indicate that ginkgo, when taken at sufficient doses and for more than 5 months, can temporarily stabilize mental and social function in people with mild to moderate dementia.
For various health conditions, a small amount of evidence suggests a benefit from taking ginkgo. Ginkgo may
Modestly help decrease symptoms of some disorders, such as anxiety and schizophrenia
Help with recovery from a stroke
Help to slow age-related macular degeneration (an eye disease) and improve blood flow in the eye
Relieve ringing in the ears, but likely not in people whose main problem is tinnitus
Prevent altitude sickness in some people
Emerging evidence reports the benefit of ginkgo in treatment of type 2 diabetesginkgo significantly decreased fasting glucose and HbA1C.
Side Effects of Ginkgo
Nausea, digestive upset, headache, dizziness, and heart palpitations may occur in people who take ginkgo. It should not be used by pregnant women because it may lead to early labor or excessive bleeding during childbirth. Gingko also should be stopped at least 2 weeks before surgery because of the potential for excessive bleeding.
Drug Interactions with Ginkgo
GinkgoGinkgo may also reduce the effectiveness of antiseizure medications and antidepressants that affect serotonin, such as selective serotonin reuptake inhibitors (SSRIsSNRIs).
Recommendations for Ginkgo
Ginkgo is relatively safe and provides a small benefit for people with peripheral arterial disease and possibly various other health conditions. People taking medications that may interact with ginkgo should consult with their doctor before taking ginkgo supplements. It is also important to stop using ginkgo 2 weeks before surgery.
More Information
The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
National Institutes of Health's National Center for Complementary and Integrative Health: Ginkgo
