At a glance: Ginkgo is the leaf of Ginkgo biloba L., the only living species of an ancient lineage of seed plants. Modern clinical evidence concerns standardised leaf extracts, not raw leaf tea and certainly not the seeds. Large trials have not shown that ginkgo prevents dementia, while some meta-analyses suggest modest symptomatic benefit in people who already have dementia. The distinction between prevention and symptomatic treatment is essential.[1][2][3]
Botanical profile
- Accepted name: Ginkgo biloba L.
- Common names: ginkgo, maidenhair tree.
- Family: Ginkgoaceae.
- Medicinal part: leaf.
- EMA herbal drug name: Ginkgo folium.[1]
Ginkgo biloba is often described as a “living fossil” because it is the sole surviving species of a very old plant lineage. It is a deciduous tree with distinctive fan-shaped leaves, usually divided into two lobes to varying degrees.
Major constituent groups
Ginkgo leaf contains a complex mixture, but standardised medicinal extracts are especially characterised by:
- Flavonoids and flavonol glycosides, including derivatives of quercetin, kaempferol and isorhamnetin.
- Terpene trilactones, principally ginkgolides A, B and C and the sesquiterpene trilactone bilobalide.
- Other phenolic compounds, proanthocyanidins and minor constituents.
- Ginkgolic acids, potentially toxic alkylphenols that are deliberately limited in well-characterised pharmaceutical extracts.[4][5]
The reduction of ginkgolic acids is one reason a pharmaceutical-grade standardised extract cannot be treated as equivalent to crude ginkgo leaf powder.
Traditional use
In Chinese materia medica the seed has the longest-established traditional use, particularly for cough, wheezing, excessive phlegm and urinary frequency. Ginkgo leaf entered modern herbal practice much later and became associated especially with peripheral circulation, cold hands and feet, age-related memory complaints and dizziness. This distinction between the traditional seed drug and the modern medicinal leaf extract is an important part of ginkgo’s history.
Contemporary herbal practice
Modern Western phytotherapy uses ginkgo primarily as a standardised-extract medicine rather than as a traditional tea herb. Practitioners most commonly consider it in age-related cognitive or circulatory presentations and pay close attention to the exact extract used, because the better-known clinical literature is tied to chemically characterised preparations. This is a case where contemporary phytotherapy has moved far beyond the plant’s older seed-centred East Asian use.
EMA regulatory assessment
The EMA HMPC monograph covers specified preparations made from dried ginkgo leaf, including a defined dry extract produced with acetone and subsequently processed to the finished extract. The EU assessment concerns the medicinal use of these characterised preparations rather than every commercially available ginkgo supplement.[1]
This is a particularly important monograph for teaching extract specificity: clinical evidence generated using a standardised extract should not be transferred automatically to unstandardised leaf powder, tea or a different extract.
Dementia prevention: what does the evidence say?
Large randomised studies have not shown that ginkgo prevents dementia. NCCIH summarises evidence from trials including the Ginkgo Evaluation of Memory study, in which more than 3,000 older adults were followed for a median of six years and ginkgo did not reduce the incidence of dementia or Alzheimer’s disease compared with placebo.[2]
Therefore, claims that ginkgo “prevents Alzheimer’s” or “protects against dementia” are not supported by the large prevention trials.
Established dementia symptoms: a different question
Some research asks whether standardised ginkgo extract can improve symptoms in people who already have dementia. A 2010 systematic review of nine trials involving 2,372 people found a pooled cognitive outcome favouring the standardised extract EGb 761 over placebo, although improvement in activities of daily living did not reach statistical significance in the pooled analysis.[3]
NCCIH describes the possibility of a modest symptomatic benefit, particularly at higher doses used in trials, but notes that the evidence is inconsistent.[2]
These findings do not contradict the failure of prevention trials: preventing a disease and modifying symptoms after disease is present are different clinical questions.
Healthy cognition and “brain boosting”
Ginkgo supplements are frequently marketed to healthy people for memory or cognitive enhancement. NCCIH concludes that evidence in healthy people is uncertain and much of the literature is low quality.[2] A study in dementia therefore cannot be cited as proof that ginkgo makes a healthy student more intelligent or improves ordinary memory.
Pharmacology
Ginkgo flavonoids and terpene trilactones have been investigated for antioxidant, vascular, platelet-activating-factor, mitochondrial and neuroprotective effects. Ginkgolides are particularly associated with antagonism of platelet-activating factor, while bilobalide has been investigated in experimental neurological models.[5][6]
These mechanisms are biologically interesting but do not establish clinical benefit by themselves.
Preparations
Relevant preparations include standardised dry extracts and, commercially, many less well-characterised supplements. Raw or home-prepared ginkgo leaf should not be assumed to match the composition, safety or evidence of the standardised extracts used in clinical studies.
Ginkgo seeds are a separate safety issue. Fresh ginkgo seeds are toxic when eaten, and serious adverse effects have also occurred after consumption of roasted seeds or crude plant material.[2]
Safety
Standardised ginkgo leaf extracts are generally tolerated by many adults, with reported adverse effects including headache, dizziness and gastrointestinal symptoms.[2]
The safety profile of a purified, standardised leaf extract should not be used to reassure people about crude seed or uncharacterised plant products.
Bleeding and anticoagulants
Ginkgo may increase bleeding risk, particularly in people taking anticoagulant or antiplatelet medicines. NCCIH specifically highlights warfarin as an interaction concern.[2]
Not every mechanistic platelet effect becomes a clinically important bleed, but a medication review is appropriate before medicinal-dose ginkgo is added to anticoagulant or antiplatelet treatment.
Pregnancy and breastfeeding
NCCIH advises that ginkgo may be unsafe in pregnancy because of concerns about early labour or additional bleeding around delivery, while breastfeeding safety is poorly characterised.[2]
Student note: common evidence traps
- Do not cite dementia-treatment trials as evidence that ginkgo prevents dementia.
- Do not transfer evidence from standardised EGb 761 to generic ginkgo tea or leaf powder.
- Separate leaf extract from seed toxicity.
- Do not convert antioxidant or neuroprotective mechanisms into a claim of clinical cognitive enhancement.
- Record extract standardisation and ginkgolic-acid limits when comparing products.
- Distinguish statistical improvement in cognitive scales from meaningful improvement in activities of daily living.
References
- European Medicines Agency, Committee on Herbal Medicinal Products. Ginkgo folium — Ginkgo biloba L., folium. EU herbal monograph and assessment report. EMA. Final monograph published 2015; periodic-review data call completed 2022.
- National Center for Complementary and Integrative Health. Ginkgo: Usefulness and Safety. NCCIH. Consulted September 2026.
- Weinmann S, Roll S, Schwarzbach C, Vauth C, Willich SN. Effects of Ginkgo biloba in dementia: systematic review and meta-analysis. BMC Geriatrics. 2010;10:14. PubMed.
- Wang S, et al. Advances in the chemical constituents and chemical analysis of Ginkgo biloba leaf, extract, and phytopharmaceuticals. Journal of Pharmaceutical and Biomedical Analysis. 2021;193:113704. doi:10.1016/j.jpba.2020.113704. PubMed.
- Rather LJ, et al. Ginkgo biloba: traditional use, phytochemistry, pharmacology and therapeutic applications. American Journal of Chinese Medicine. 2025;53(8):2403–2434. PubMed.
- Lu J, et al. Bilobalide: a review of its pharmacology, pharmacokinetics, toxicity and safety. Phytotherapy Research. 2021;35(11):6114–6130. doi:10.1002/ptr.7220. PubMed.
Additional materia medica sources
- ESCOP. Ginkgo folium — Ginkgo leaf, ESCOP Monographs.
- Blumenthal M, et al., eds. The Complete German Commission E Monographs. American Botanical Council; 1998.
- World Health Organization. WHO Monographs on Selected Medicinal Plants and later technical reviews addressing Ginkgo biloba.
- Mills S, Bone K. Principles and Practice of Phytotherapy. 2nd ed. Elsevier; 2013.
Last reviewed: 20 September 2026. Educational reference only; not an individual dosing or prescribing guide.
← Return to the Herbal Monograph Library | Herbal Medicine Safety and Interactions