Latin Name— Ginkgo biloba
Historically, Ginkgo leaf extract has been used as an herbal remedy for a variety of problems, including asthma, bronchitis, fatigue, and tinnitus (ringing or roaring sounds in the ears).
Extracts are taken from the ginkgo leaf and are used to make tablets, capsules, or teas. Occasionally, ginkgo extracts are used in skin products.
Warning Fresh (raw) ginkgo seeds contain large amounts of a chemical called ginkgotoxin, which can cause serious adverse reactions—even seizures and death. See below for Side Effects and Cautions Summary.
Recently people use ginkgo leaf extracts hoping to improve such concerns as:
- Alzheimer’s disease and other types of dementia,
- intermittent claudication (leg pain caused by narrowing arteries),
- sexual dysfunction,
- multiple sclerosis,
- and other health conditions.
Research on Ginkgo Leaf Extract
Numerous studies of ginkgo leaf extract have been done for a variety of conditions. Among the most widely researched are dementia, memory impairment, intermittent claudication, and tinnitus.
An NCCAM-funded study of the well-characterized ginkgo leaf extract product EGb-761 found it ineffective in lowering the overall incidence of dementia and Alzheimer’s disease in the elderly. Further analysis of the same data also found ginkgo leaf extract to be ineffective in slowing cognitive decline, lowering blood pressure, or reducing the incidence of hypertension. In this clinical trial, known as the Ginkgo Evaluation of Memory study, researchers recruited more than 3,000 volunteers age 75 and over who took 240 mg of ginkgo leaf extract daily. Participants were followed for an average of approximately 6 years.
Some smaller studies of ginkgo for memory enhancement have had promising results, but a trial sponsored by the National Institute on Aging of more than 200 healthy adults over age 60 found that ginkgo taken for 6 weeks did not improve memory.
Overall, the evidence on ginkgo leaf extract for symptoms of intermittent claudication has not yet shown a significant benefit for this condition, although several small studies have found modest improvements. There is conflicting evidence on the efficacy of ginkgo for tinnitus.
Other NCCAM-funded research includes studies of ginkgo leaf extract for symptoms of multiple sclerosis, intermittent claudication, cognitive decline, sexual dysfunction due to antidepressants, insulin resistance, and short-term memory loss associated with electroconvulsive therapy for depression.
Side Effects and Cautions Summary
- Fresh (raw) ginkgo seeds contain large amounts of a chemical called ginkgotoxin, which can cause serious adverse reactions—even seizures and death. Roasted seeds can also be dangerous. Products made from standardized ginkgo leaf extracts contain little ginkgotoxin and appear to be safe when used orally and appropriately.
- Side effects of ginkgo leaf extract may include headache, nausea, gastrointestinal upset, diarrhea, dizziness, or allergic skin reactions. More severe allergic reactions have occasionally been reported.
- There are some data to suggest that ginkgo leaf extract can increase bleeding risk, so people who take anticoagulant drugs, have bleeding disorders, or have scheduled surgery or dental procedures should use caution and talk to a health care provider if using ginkgo leaf extract.
- Tell your health care providers about any complementary and alternative practices you use. Give them a full picture of what you do to manage your health to help ensure coordinated and safe care. Complementary or alternative therapy should not be used in place of conventional medical care or to delay seeking that care.
- Brinkley TE, Lovato JF, Arnold AM, et al. Effect of Ginkgo biloba on blood pressure and incidence of hypertension in elderly men and women. American Journal of Hypertension. 2010;23(5):528–533.
- DeKosky ST, Williamson JD, Fitzpatrick AL, et al. Ginkgo biloba for prevention of dementia: a randomized controlled trial. Journal of the American Medical Association. 2008;300(19):2253–2262.
- Ginkgo. Natural Medicines Comprehensive Database Web site. Accessed at www.naturaldatabase.com on August 20, 2009.
- Ginkgo (Ginkgo biloba L.). Natural Standard Database Web site. Accessed at www.naturalstandard.com on August 20, 2009.
- Ginkgo biloba. In: Coates P, Blackman M, Cragg G, et al., eds. Encyclopedia of Dietary Supplements. New York, NY: Marcel Dekker; 2005:249–257.
- Ginkgo biloba leaf extract. In: Blumenthal M, Goldberg A, Brinckman J, eds. Herbal Medicine: Expanded Commission E Monographs. Newton, MA: Lippincott Williams & Wilkins; 2000:359–366.
- Snitz BE, O’Meara ES, Carlson MC, et al. Ginkgo biloba for preventing cognitive decline in older adults: a randomized trial. Journal of the American Medical Association. 2009;302(24):2663–2670.
- Solomon PR, Adams F, Silver A, et al. Ginkgo for memory enhancement: a randomized controlled trial. Journal of the American Medical Association. 2002;288(7):835–840.
For More Information
The National Center for Complementary and Alternative Medicine (NCCAM) Clearinghouse
The NCCAM Clearinghouse provides information on CAM and NCCAM, including publications and searches of Federal databases of scientific and medical literature. The Clearinghouse does not provide medical advice, treatment recommendations, or referrals to practitioners.
NIH Office of Dietary Supplements
Web site: ods.od.nih.gov
NIH National Library of Medicine’s MedlinePlus
Ginkgo Listing: www.nlm.nih.gov/medlineplus/druginfo/natural/patient-ginkgo.html
Source: National Center for Complementary and Alternative Medicine, Ginkgo Biloba fact sheet, Created September 2005, Updated July 2010