Ginkgo biloba is one of the oldest and most studied herbal supplements, with over 400 clinical trials. Our research shows moderate evidence for peripheral artery disease (claudication), tinnitus, and cognitive function in dementia — but a large NIH-funded trial (GEM study, 3,069 participants) found NO benefit for preventing dementia or cognitive decline in healthy elderly. The bleeding risk is clinically significant — ginkgo should be stopped before surgery and avoided with blood thinners.
The standardized extract (EGb 761) contains flavone glycosides (24%) and terpene lactones (6% — ginkgolides and bilobalide). Mechanisms include: increased cerebral blood flow, platelet-activating factor (PAF) antagonism, antioxidant activity, and neuroprotective effects. The PAF antagonism is why ginkgo increases bleeding risk — it literally blocks platelet activation.
PAF antagonism → increased bleeding risk; case reports of hemorrhage
Additive antiplatelet effects → bleeding risk
Ginkgo has serotonergic properties; additive effects + bleeding risk
May reduce seizure threshold (controversial)
In vitro CYP induction; clinical significance variable
May reduce alprazolam levels via CYP3A4 induction
Case report of coma when combined with ginkgo
Discontinue ginkgo at least 2 weeks before surgery due to antiplatelet effects.
Not Prohibited
DeKosky ST et al. Ginkgo biloba for prevention of dementia (GEM study). *JAMA.* 2008.
(2008). PMID: 19017911
Pittler MH, Ernst E. Ginkgo biloba extract for treatment of intermittent claudication.
Laws KR et al. Is Ginkgo biloba a cognitive enhancer in healthy individuals? A meta-analysis.
Bent S et al. Spontaneous bleeding associated with ginkgo biloba.
Reviewed by the Scan Dose Research Team and Clinical Advisory Board | Last updated: April 2026
Not medical advice. Based on published clinical research and systematic reviews.
Safety
Dangerous interactions. Talk to your prescriber before using this supplement if you take any of these.
Warfarin and other anticoagulants
Ginkgo inhibits platelet-activating factor (PAF).
Source: FDA MedWatch reports
Aspirin and NSAIDs
Additive antiplatelet effect.
Source: Clinical pharmacology
Moderate interactions. Monitoring, timing separation, or dose adjustment may be required.
Seizure medications (valproate, phenytoin)
Ginkgo may lower seizure threshold.
Source: Case reports
CYP2C9 substrates
Ginkgo may induce CYP2C9.
Source: In vitro data
Stop 2 weeks before surgery
Bleeding risk from PAF inhibition.
Educational information only. This is not medical advice. These statements have not been evaluated by the FDA. Talk to your prescriber before starting, stopping, or combining any supplement with prescription medication.