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Ginkgo (Ginkgo biloba)

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Related terms
Background
Evidencetable
Tradition
Dosing
Safety
Interactions
Attribution
Bibliography

Related Terms
  • Adiantifolia, AKL1, arbre aux quarante écus (French), ArginMax®, bai guo ye, baiguo, BioGinkgo®, Blackmores Ginkgo Brahmi (Bacopa monniera), BN-52063, duck foot tree, EGb, EGb 761, Elefantenohr (German), eun-haeng (Korean), Fächerblattbaum, fossil tree, GBE, GBE 24, GBX, ginan, Gincosan®, Ginexin Remind®, gingko, Gingopret®, Ginkai®, ginkgo balm, Ginkgo biloba Blätter (German), Ginkgo biloba exocarp polysaccharides (GBEP), Ginkgo folium, Ginkgo Go®, Ginkgo Phytosome®, Ginkgo Powder®, Ginkgoaceae (family), Ginkgoblätter (German), ginkgogink, ginkgold, Ginkgold®, ginkgopower, Ginkopur®, ginkyo, gin-nan (Japanese), Herbal vX®, icho (Japanese), ityo, Japanbaum (German), Japanese silver apricot, kew tree, kung sun shu, LI 1370, maidenhair tree, noyer du Japon (French), Oriental plum tree, pei kuo, pei-wen, Pterophyllus, Pterophyllus salisburiensis, Rö Kan®, Rökan, salisburia, Salisburia adiantifolia, Salisburia macrophylla, Seredrin®, silver apricot, sophium, Tanakan®, tanakene, tebofortan, Tebonin®, tempeltrae, temple balm, tramisal, valverde, vasan, vital, ya chio, yin-guo, yin-hsing (Chinese).

Background
  • Ginkgo biloba has been used medicinally for thousands of years. Today, it is one of the top-selling herbs in the United States.
  • Ginkgo is used for the treatment of numerous conditions, many of which are under scientific investigation. Available evidence demonstrates ginkgo's efficacy in the management of intermittent claudication, Alzheimer's/multi-infarct dementia, and "cerebral insufficiency" (a syndrome thought to be secondary to atherosclerotic disease, characterized by impaired concentration, confusion, decreased physical performance, fatigue, headache, dizziness, depression, and anxiety).
  • Although not definitive, there is promising early evidence favoring the use of ginkgo for memory enhancement in healthy subjects, altitude (mountain) sickness, symptoms of premenstrual syndrome (PMS), age-related eye disorders, and the reduction of chemotherapy-induced end-organ vascular damage.
  • The herb is generally well tolerated, but due to multiple case reports of bleeding, it should be used cautiously in patients on anticoagulant therapy and those with known blood clotting disorders, or prior to some surgical or dental procedures.

Evidence Table

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. GRADE *


Numerous studies suggest that Ginkgo biloba taken by mouth causes small improvements in claudication symptoms (leg pain with exercise or at rest due to clogged arteries). However, ginkgo may not be as helpful for this condition as exercise therapy or prescription drugs.

A


Overall, the scientific literature does suggest that ginkgo benefits people with early-stage Alzheimer's disease and multi-infarct dementia, and it may be as helpful as acetylcholinesterase inhibitor drugs such as donepezil (Aricept®). Well-designed research comparing ginkgo to prescription drug therapies is needed.

A


Multiple clinical trials have evaluated ginkgo for a syndrome called "cerebral insufficiency." This condition, more commonly diagnosed in Europe than the United States, may include poor concentration, confusion, absentmindedness, decreased physical performance, fatigue, headache, dizziness, depression, and anxiety. It is believed that cerebral insufficiency is caused by decreased blood flow to the brain due to clogged blood vessels. Some research has reported benefits of ginkgo in patients with these symptoms, but most have been poorly designed and without reliable results.

B


In early research, ginkgo was shown to be effective in the treatment of patients with acute hemorrhoidal attacks. Further research is needed to confirm these results.

C


Age-associated memory impairment (AAMI) is a nonspecific syndrome, which may be caused by early Alzheimer's disease or multi-infarct dementia (conditions for which ginkgo has been shown to have benefit). There is preliminary research showing small improvements in memory and other brain functions in patients with AAMI, although some studies disagree. Better studies are needed before a firm conclusion can be made.

C


A small amount of poorly designed research has reported benefits of ginkgo for the treatment of altitude (mountain) sickness. Additional research is needed before a firm conclusion can be made.

C


Ginkgo may reduce symptoms in patients with asthma. More research is needed to make a firm conclusion.

C


Animal and limited human data suggest a role in heart blood flow. More research is needed in this area.

C


In limited human research, ginkgo has been examined in addition to 5-fluorouracil (5-FU) in the treatment of pancreatic and colorectal cancer, to measure possible benefits on side effects. At this time, there is a lack of conclusive evidence in this area.

C


Research is unclear in this area. However, a multi-ingredient product called Ginkor Fort® may aid in the treatment of patients with lower limb chronic venous insufficiency. Further research is needed, and firm conclusions cannot be made at this point.

C


It is not clear whether ginkgo is helpful in treating cocaine dependence. More research is needed.

C


Based on human research, Ginkgo biloba in patients with multiple sclerosis may improve cognitive function. More well-designed trials are needed before a firm conclusion can be made.

C


Preliminary research on seasonal affective disorder (SAD) suggests that ginkgo is not effective in preventing the development of winter depression. Other research in elderly patients with depression shows possible minor benefits. Overall, there is not enough evidence to form a clear conclusion.

C


Research is unclear in this area. Ginkgo may help improve some laboratory parameters associated with diabetic neuropathy, but more research is needed to make a firm conclusion.

C


Ginkgo is traditionally used for improved memory or cognition and research supports a possible use for patients with dyslexia. More research is needed in this area.

C


Ginkgo biloba exocarp polysaccharide (GBEP) capsule preparation has been studied for upper digestive tract malignant tumors of middle and late stages, with positive results. However, further research is needed before a conclusion can be made.

C


It is not clear if ginkgo may improve intraocular pressure and blood flow in patients with glaucoma. Some study results conflict or have not been significant. Further research is needed before a conclusion can be made.

C


Ginkgo may decrease damage to cells caused by radioiodine therapy in patients with Graves' disease. Further research is needed.

C


Preliminary research suggests that ginkgo may improve eye blood flow, although it remains unclear if macular degeneration is significantly affected by ginkgo. More research is needed in this area before a conclusion can be drawn.

C


It remains unclear if ginkgo is effective. Further well-designed research is needed, as existing study results conflict.

C


It remains unclear if ginkgo is effective for mood and cognition improvement. Further well-designed research is needed, as existing research has reported conflicting evidence.

C


Based on laboratory research, it has been suggested that ginkgo may provide benefit in multiple sclerosis (MS). Human research is limited to several small studies, which have not found consistent benefit. Additional research is needed before a conclusion can be made.

C


Initial research has not shown any effect of Ginkgo on peripheral artery disease. More studies are needed before a conclusion can be made.

C


Initial research in women with premenstrual syndrome (PMS) or breast discomfort suggests that ginkgo may relieve symptoms, including emotional upset. Further well-designed research is needed before a conclusion can be made.

C


Based on early research, ginkgo may be effective in treating pulmonary interstitial fibrosis. Further research is needed to confirm these results.

C


Early studies suggest that ginkgo may aid in quality of life. More randomized controlled trials are needed before a conclusion can be made.

C


Results from one clinical trial suggest that Ginkgo biloba may be effective in reducing the number of attacks in patients suffering from Raynaud's disease. In order to confirm these results, further clinical trials are required.

C


Early research suggests that Ginkgo biloba extract may offer benefit to individuals with retinopathy. Further clinical trials are required to determine efficacy.

C


Based on its proposed antioxidant effects, ginkgo has been studied in the treatment of schizophrenia. Although early research is promising, there is currently not enough scientific evidence to make a firm conclusion.

C


Ginkgo has been used and studied for the treatment of sexual dysfunction in men and women. In general, the studies were small and not well designed. Additional research is needed before a conclusion can be made.

C


Laboratory studies suggest that ginkgo may be helpful immediately following strokes, because of possible antioxidant or blood vessel effects. However, initial study of ginkgo in people having strokes found a lack of benefit. Further research is needed in this area.

C


There is conflicting research regarding the use of ginkgo for tinnitus. Additional well-designed research is needed in order to resolve this controversy.

C


A small amount of poorly designed research has reported benefits of ginkgo for the treatment of vertigo. Additional research is needed before a conclusion can be made.

C


Early research using oral Ginkgo biloba extract has reported that ginkgo appears to arrest the progression of this disease. Better-designed studies are needed to confirm these results.

C


The results of one study investigating the effect of Ginkgo biloba on postprandial mental alertness are unclear. Ginkgo may benefit some but not all endpoints. Further clinical trials are required before conclusions can be made.

D
* Key to grades

A: Strong scientific evidence for this use
B: Good scientific evidence for this use
C: Unclear scientific evidence for this use
D: Fair scientific evidence for this use (it may not work)
F: Strong scientific evidence against this use (it likley does not work)


Tradition / Theory

The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

  • Acidosis, adaptogen, aging, alcoholism, allergies, angina, antibacterial, antifungal, anti-inflammatory, antioxidant, antiparasitic, antirheumatic, antitumor, anxiety, arthritis, attention-deficit hyperactivity disorder, autoimmune disorders, bladder disorders, blood clots, blood vessel disorders, body fat reducer (cellulite), brain damage, breast disease, breast tenderness, bronchitis, cancer, cataracts, chest pain, chilblains (inflammation of toes, fingers, ears, or face with exposure to cold), chronic rhinitis, colorectal cancer, congestive heart failure, contraceptive, cough, cyanosis, degenerative diseases (prevention), dermatitis, diabetes, digestion, dizziness, dysentery (bloody diarrhea), eczema, edema, encephalopathy (circulatory), expectorant, fatigue, fibromyalgia, freckle-removing, genitourinary disorders, headache, hearing loss, heart attack, hepatitis B, high blood pressure, high cholesterol, hypoxia (lack of oxygen), immunomodulator, insomnia, labor induction, menstrual pain, migraine, mouth cancer, respiratory tract illnesses, scabies (ginkgo cream), seizures, sepsis, skin sores (ginkgo cream), spermicide, sports performance, swelling, stress, traumatic brain injury, ulcer (trophic lesions), ulcerative colitis, vaginal dryness, varicose veins, vision (color).

Dosing

Adults (over 18 years old)

  • Traditional recommendations include ginkgo products containing 24% flavoglycosides (also called flavone glycosides or flavones) and 6% terpenes: 80-240 milligrams of a 50:1 standardized leaf extract daily, or 3-6 milliliters of a 40 milligram per milliliter liquid extract in 2-3 divided doses, or 30-40 milligrams of extract in a tea bag, prepared as a tea, for at least 4-6 weeks. There is a lack of evidence in support of the clinical benefit of small concentrations of ginkgo found in fortified foods. All doses above are oral unless otherwise stated. Beneficial effects may take 4-6 weeks to appear. Ginkgo seeds are potentially toxic and should be avoided. The intravenous ginkgo product Tebonin®, which was available in Germany, was removed from the German market due to significant adverse effects.
  • 40-240 milligrams of extract, tincture, or powder has been taken by mouth daily, divided into two or three doses. Beneficial effects may take 4-6 weeks to appear. Patients have also been treated with intravenous ginkgo preparations: 0.7 milligrams of intravenous extract per minute for 120 minutes; 100 milligrams of ginkgo in 500 cubic centimeters of normal saline, administered twice daily; 20 milliliters of ginkgo in 250 milliliters of normal saline daily for four weeks; and 200 milligrams of EGb 761 infusion for 10 days, followed by a twice-daily oral dose of 80 milligrams for 12 weeks.

Children (under 18 years old)

  • Dyslexia: A single 80 milligram dose of EGb 761 daily for an average of 34.4 days.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

  • Allergy or hypersensitivity to Ginkgo biloba or members of the Ginkgoaceae family may occur. A severe reaction, called Stevens-Johnson syndrome, which includes skin blistering and sloughing-off, has been reported with use of a combination product. There may be cross-sensitivity to ginkgo in people allergic to urushiols (mango rind, poison sumac, poison ivy, poison oak, cashews), and an allergic cross-reaction has been reported in a person allergic to poison ivy.

Side Effects and Warnings

  • Overall, ginkgo leaf extract (used in most commercial products) appears to be well tolerated in most healthy adults at suggested doses for up to six months. Minor symptoms, including headache, nausea, and intestinal complaints have been reported.
  • Ginkgo may be unsafe in children.
  • Ginkgo may increase the risk of stroke.
  • Ginkgo may theoretically affect insulin and blood sugar levels. Caution is advised in patients with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugar. Serum glucose levels may need to be monitored by a healthcare professional, and medication adjustments may be necessary.
  • There have been uncommon reports of dizziness, stomach upset, diarrhea, vomiting, muscle weakness, loss of muscle tone, restlessness, racing heart, rash, and irritation around the mouth with the use of ginkgo. There is a case report of "coma" in an elderly Alzheimer's patient taking trazodone and ginkgo, although it is not clear that ginkgo was the cause.
  • Ginkgo may decrease blood pressure, although there is one report of ginkgo possibly raising blood pressure in a person taking a thiazide diuretic ("water pill").
  • High concentrations of ginkgo may reduce male and female fertility.
  • Contamination with the drug colchicine has been found in commercial preparations of Ginkgo biloba.
  • Bleeding has been associated with the use of ginkgo taken by mouth, and caution is advised in patients with bleeding disorders or those taking drugs, herbs, or supplements that may increase the risk of bleeding. Dosing adjustments may be necessary. Ginkgo should be stopped prior to some surgical or dental procedures. Reports of bleeding range from nose bleeds to life-threatening bleeding in several case reports. In some of these reports, ginkgo has been used with other agents that may also cause bleeding.
  • Eating fresh ginkgo seeds is potentially deadly, due to the risk of tonic-clonic seizures and loss of consciousness.
  • Ginkgo may affect the outcome of electroconvulsive therapy (ECT). Adverse effects on the eyes have also been reported.

Pregnancy and Breastfeeding

  • Use of ginkgo is not suggested during pregnancy and breastfeeding, due to the lack of reliable scientific study in this area. The risk of bleeding associated with ginkgo may be dangerous during pregnancy.

Interactions

Interactions with Drugs

  • Overall, ginkgo trials have had few reported adverse effects and good tolerance, with rates of complications similar to placebo.
  • Use of ginkgo with drugs that may cause bleeding may further increase the risk of bleeding, based on multiple case reports of spontaneous bleeding in patients using ginkgo alone, with warfarin (Coumadin®), or with aspirin. One case report documents a possible increase in bleeding risk with ticlopidine (Ticlid®) and ginkgo. Examples of drugs that may increase the risk of bleeding include aspirin, anticoagulants (blood thinners) such as warfarin (Coumadin®) or heparin, antiplatelet drugs such as clopidogrel (Plavix®), and nonsteroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®). However, not all studies agree with the existence of this risk, and it is not clear if particular types of patients may be at greater risk.
  • Ginkgo may affect insulin and blood sugar levels. Caution is advised when using medications that may also lower blood sugar. Patients taking insulin or drugs for diabetes by mouth should be monitored closely by a qualified healthcare professional. Medication adjustments may be necessary.
  • Ginkgo has been found to decrease blood pressure in healthy volunteers, although some studies disagree. Theoretically, ginkgo may add to the effects of medications that also lower blood pressure, although raised blood pressure has been reported in a patient taking a thiazide diuretic ("water pill") with ginkgo. It has been suggested that Ginkgo biloba leaf extract (GBE) and nifedipine should not be ingested at the same time.
  • There may be a risk of seizure when taking ginkgo, particularly in people with a history of seizure disorder. Although most reports of seizures have been due to eating ginkgo seeds (not leaf extract, which is found in most products), the antiseizure properties of sodium valproate or carbamazepine were reduced by giving ginkgo. In theory, drugs such as donepezil (Aricept®) and tacrine (Cognex®) may have an additive effect when used at the same time as ginkgo, potentially increasing cholinergic effects (such as salivation and urination).
  • Ginkgo may also interact with the following: agents that may lower the seizure threshold, Alzheimer's agents, asthma agents, antidepressants (SSRIs and MAOIs), antihistamines, anti-inflammatories, antilipemics, antineoplastics, antipsychotics, antitinnitus agents, antivertigo agents, colchicine, CYP450-metabolized agents, diuretics, hormonal agents, impotence agents, iodine, nifedipine, olanzapine, prednisone, renally eliminated agents, trazodone, and vasodilators.
  • Ginkgo may enhance the effects of clozapine on the negative symptoms in patients with schizophrenia.

Interactions with Herbs and Dietary Supplements

  • Use of ginkgo with herbs or supplements that may cause bleeding may increase the risk of bleeding, although some studies disagree. Several cases of bleeding have been reported with the use of garlic, as have two cases with saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.
  • Ginkgo has been found to decrease blood pressure in healthy volunteers, although some studies disagree. Theoretically, ginkgo may have additive effects when used with herbs or supplements that also decrease blood pressure. However, high blood pressure was reported in a patient taking a diuretic ("water pill") plus ginkgo. Although it remains unclear if ginkgo has clinically significant effects on blood pressure, caution may be warranted when ginkgo is used with other agents that affect blood pressure.
  • Ginkgo may theoretically affect insulin and lower blood sugar levels. Caution is advised when using herbs or supplements that may also affect blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.
  • There may be a risk of seizure when taking ginkgo, particularly in people with a history of seizure disorder.
  • Ginkgo may also interact with the following: agents that may lower the seizure threshold, Alzheimer's agents, asthma agents, antidepressants (SSRIs and MAOIs), antihistamines, anti-inflammatories, antilipemics, antineoplastics, antipsychotics, antitinnitus agents, antivertigo agents, athletic performance enhancers, CYP450-metabolized agents, diuretics, ginger, hormonal agents, impotence agents, iodine, renally eliminated agents, St. John's wort, vasodilators, and yohimbe.

Attribution
  • This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Bibliography
  1. Birks J, Grimley Evans J. Ginkgo biloba for cognitive impairment and dementia. Cochrane Database Syst Rev 2007 Apr 18;(2):CD003120.
  2. Carlson JJ, Farquhar JW, DiNucci E, et al. Safety and efficacy of a ginkgo biloba-containing dietary supplement on cognitive function, quality of life, and platelet function in healthy, cognitively intact older adults. J Am Diet Assoc 2007 Mar;107(3):422-32.
  3. DeKosky, S. T., Williamson, J. D., Fitzpatrick, A. L., Kronmal, R. A., Ives, D. G., Saxton, J. A., Lopez, O. L., Burke, G., Carlson, M. C., Fried, L. P., Kuller, L. H., Robbins, J. A., Tracy, R. P., Woolard, N. F., Dunn, L., Snitz, B. E., Nahin, R. L., and Furberg, C. D. Ginkgo biloba for prevention of dementia: a randomized controlled trial. JAMA 11-19-2008;300(19):2253-2262.
  4. Gardner, C. D., Taylor-Piliae, R. E., Kiazand, A., Nicholus, J., Rigby, A. J., and Farquhar, J. W. Effect of Ginkgo biloba (EGb 761) on treadmill walking time among adults with peripheral artery disease: a randomized clinical trial. J Cardiopulm.Rehabil Prev. 2008;28(4):258-265.
  5. Hilton M, Stuart E. Ginkgo biloba for tinnitus. Cochrane Database Syst Rev 2004;(2):CD003852.
  6. Issing W, Klein P, Weiser M. The homeopathic preparation Vertigoheel versus Ginkgo biloba in the treatment of vertigo in an elderly population: a double-blinded, randomized, controlled clinical trial. J Altern Complement Med 2005;11(1):155-160.
  7. Kampman K, Majewska MD, Tourian K, et al. A pilot trial of piracetam and ginkgo biloba for the treatment of cocaine dependence. Addict Behav 2003;28(3):437-448.
  8. Kohler S, Funk P, Kieser M. Influence of a 7-day treatment with Ginkgo biloba special extract EGb 761 on bleeding time and coagulation: a randomized, placebo-controlled, double-blind study in healthy volunteers. Blood Coagul Fibrinolysis 2004;15(4):303-309.
  9. Lovera J, Bagert B, Smoot K, et al. Ginkgo biloba for the improvement of cognitive performance in multiple sclerosis: a randomized, placebo-controlled trial. Mult Scler 2007 Apr;13(3):376-85.
  10. Napryeyenko O, Borzenko I; GINDEM-NP Study Group. Ginkgo biloba special extract in dementia with neuropsychiatric features. A randomised, placebo-controlled, double-blind clinical trial. Arzneimittelforschung 2007;57(1):4-11.
  11. Robertson SM, Davey RT, Voell J, et al. Effect of Ginkgo biloba extract on lopinavir, midazolam and fexofenadine pharmacokinetics in healthy subjects. Curr Med Res Opin 2008 Feb;24(2):591-9.
  12. Thomas M, Sheran J, Smith N, et al. AKL1, a botanical mixture for the treatment of asthma: a randomised, double-blind, placebo-controlled, cross-over study. BMC Pulm Med. 2007 Mar 20;7:4.
  13. Wolf HR. Does Ginkgo biloba special extract EGb 761 provide additional effects on coagulation and bleeding when added to acetylsalicylic acid 500 mg daily? Drugs R D 2006;7(3):163-72.
  14. Yoshioka, M., Ohnishi, N., Koishi, T., Obata, Y., Nakagawa, M., Matsumoto, T., Tagagi, K., Takara, K., Ohkuni, T., Yokoyama, T., and Kuroda, K. Studies on interactions between functional foods or dietary supplements and medicines. IV. Effects of ginkgo biloba leaf extract on the pharmacokinetics and pharmacodynamics of nifedipine in healthy volunteers. Biol.Pharm.Bull. 2004;27(12):2006-2009.
  15. Zeng X, Liu M, Yang Y, et al. Ginkgo biloba for acute ischaemic stroke. Cochrane Database Syst Rev 2005 Oct 19;(4):CD003691.

Copyright © 2011 Natural Standard (www.naturalstandard.com)


The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.


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