Ginkgo
Ginkgo: what NIH says (including a large trial that found no effect on dementia), bleeding risk with anticoagulants, and the toxicity of ginkgo seeds.
Content last updated . This page has not been medically reviewed.
Safety first. Supplements can cause side effects and interact with medicines. Read mushroom safety and interactions before you use any mushroom product.
Fresh ginkgo seeds are toxic. Serious side effects have occurred in people who ate roasted seeds or crude ginkgo plant. [1]
Overview
Ginkgo is an ancient deciduous tree, the last remaining species of a primitive plant family. It has a long history in Chinese medicine for cough and diarrhea. Leaf extract is the most common form, promoted for anxiety, heart disease, dementia, diabetes, PMS, tinnitus and cognitive performance. [1]Names and parts
Ginkgo biloba. [1][2] The leaf extract is the form used in studies; the seed is toxic. [1]What the research shows (NIH summary)
NIH says ginkgo has not been shown to be effective for any of the conditions studied, and there is no conclusive evidence it helps any health condition. [1]| Use | What NIH says | Strength of evidence |
|---|---|---|
| Preventing or slowing dementia | Not shown. Three large studies in older adults did not reduce dementia risk. In the NIH-funded GEM study, more than 3,000 people aged 75 or older took ginkgo or placebo for a median of 6 years, with no difference in dementia or Alzheimer's rates. [1] | Negative |
| Dementia symptoms | A modest benefit is possible, especially at relatively high doses, but the evidence is inconsistent. [1] | Inconsistent |
| Cognitive performance in healthy people | Uncertain; much research is low quality. [1] | Uncertain |
| Heart disease, high blood pressure, tinnitus, multiple sclerosis | Research suggests it is not helpful. [1] | Negative |
| Anxiety, PMS, schizophrenia, vertigo | A small amount of evidence suggests a benefit, not conclusive. [1] | Limited |
Safety
- Leaf extracts are likely safe for most adults in moderate amounts, and were used safely in studies lasting as long as 6 years. Common side effects: dizziness, stomach symptoms and headache. [1]
- Bleeding: ginkgo may increase the risk of bleeding in people taking anticoagulants such as warfarin, and may interact with other medicines. [1]
- It may be unsafe in pregnancy: it might cause early labor or extra bleeding near delivery. Little is known about breastfeeding. [1]
Frequently asked questions
Does ginkgo improve memory?
NIH says it is uncertain for healthy people, and a large trial found no reduction in dementia. [1]
Is ginkgo safe with blood thinners?
It may increase bleeding risk with anticoagulants such as warfarin. [1]
References
- National Center for Complementary and Integrative Health (NIH). Ginkgo: Usefulness and Safety. Page last updated February 2025.
- GBIF Secretariat. GBIF Backbone Taxonomy. Names checked 2026-10-22 through the GBIF species match service.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.