**By Steph Swarts, RMT, CNP** *Registered Massage Therapist | Certified Naturopathic Practitioner* 📅 Last Updated: December 21, 2025 ✅ Evidence-based recommendations from a licensed healthcare professional
Ginkgo biloba is one of the most popular herbal supplements worldwide, with millions of people taking this ancient tree extract hoping for better memory and circulation. While generally well-tolerated, understanding ginkgo biloba side effects is essential before starting supplementation.
Common Ginkgo Biloba Side Effects
Most people tolerate ginkgo relatively well, but ginkgo biloba side effects do occur with enough frequency to warrant attention. Clinical studies consistently identify certain effects as most common, particularly during the initial weeks of supplementation.
Digestive Issues
Among all ginkgo biloba side effects, those involving the digestive system are most frequently reported. Users commonly experience stomach upset, nausea, and diarrhea, particularly when first starting the supplement. These gastrointestinal symptoms are among the most common ginkgo biloba side effects, often hitting people right when they begin taking ginkgo.
The good news is that these digestive issues typically occur within the first week or two and often subside as your body adjusts to the supplement. Most people find that symptoms improve after this adjustment period. Taking ginkgo with food rather than on an empty stomach can significantly help minimize these effects. If digestive problems persist beyond two weeks, consider reducing your dose or discontinuing use.
Headaches and Dizziness
Headaches and dizziness rank among the most commonly reported ginkgo biloba side effects in clinical trials, appearing alongside gastrointestinal symptoms as the most frequently documented reactions. These symptoms can be particularly frustrating for people who started taking ginkgo to feel mentally sharper, only to experience discomfort instead.
The mechanism behind these effects relates to how ginkgo influences cerebral blood flow. These symptoms may occur due to changes in blood flow in the brain, which ginkgo biloba can influence through its vasodilatory effects on blood vessels. Some people experience a temporary feeling of being off-balance or lightheaded, especially during the first few weeks of use.
If you experience persistent headaches or dizziness after starting ginkgo, don’t try to “push through” the discomfort. Instead, consult your healthcare provider about adjusting your dose, changing the timing of when you take it, or discontinuing use entirely.
Serious Ginkgo Biloba Side Effects and Health Risks
While common ginkgo biloba side effects like digestive upset are usually manageable, some ginkgo biloba side effects require immediate medical attention and can be life-threatening.
Bleeding Complications
The most significant concern with ginkgo biloba is its potential to increase bleeding risk, which has been documented in multiple case reports and clinical studies. Research has documented fifteen case reports describing a temporal association between ginkgo use and bleeding events, with most involving serious medical conditions, including eight episodes of intracranial bleeding—bleeding inside the skull, which can be life-threatening.
One documented case involved a man who experienced spontaneous bleeding from his right eye (spontaneous hyphema) after taking ginkgo for just one week while also taking low-dose aspirin (80 mg daily). When he stopped taking ginkgo, the bleeding stopped and did not recur.
A 2025 study from Hai Phong International Hospital analyzed 2,647 prescriptions and found that among 747 patients analyzed for bleeding disorders, 31 (4.15%) exhibited bleeding symptoms. The study found significant correlations between ginkgo biloba extract drug interactions and both bleeding risk and abnormal coagulation test results. Components in ginkgo slow blood clotting through effects on platelet aggregation, which can be particularly dangerous for people with bleeding disorders or those taking anticoagulant medications.
However, it’s important to present the complete picture. The evidence on bleeding risk is actually mixed. A comprehensive meta-analysis of 18 randomized controlled trials involving 1,985 adults found that standardized ginkgo extract did not significantly increase bleeding risk based on hemostasis outcomes when compared to placebo. The risk appears highest when ginkgo is combined with other medications that affect blood clotting, such as warfarin, aspirin, or other antiplatelet drugs, rather than when ginkgo is used alone.
Seizure Risk
Growing scientific evidence suggests ginkgo may increase seizure risk in people with epilepsy and could reduce the effectiveness of anti-seizure medications. Two documented cases involved patients with well-controlled epilepsy who presented with recurrent seizures within two weeks of starting ginkgo extract. Both patients became seizure-free several months after discontinuing the herb.
One particularly tragic case involved a 55-year-old man who suffered a fatal breakthrough seizure. The autopsy revealed subtherapeutic levels of his seizure medications (Depakote and Dilantin), potentially explained by ginkgo’s induction of liver enzymes that metabolize these drugs more rapidly.
Animal studies have also shown concerning results, with high doses of ginkgo extract (400 mg/kg) increasing epileptic activity in rats. Researchers have identified ten reports indicating that patients with epilepsy who take ginkgo products face an increased risk of seizures.
Allergic Reactions
Allergic reactions to ginkgo can range from mild skin rashes to severe, life-threatening anaphylaxis. Documented reactions include skin rash, itching, hives, and swelling of the face, lips, tongue, or throat. Ginkgo has been identified among supplements that can cause anaphylaxis, along with Andrographis paniculata, Echinacea species, bee products, and ginseng.
If you are allergic to products containing alkylphenols, you should avoid ginkgo entirely, as it can trigger allergic reactions.
Other Serious Ginkgo Biloba Side Effects
Less common but documented ginkgo biloba side effects include:
- Heart palpitations: Rapid, pounding, or irregular heartbeat
- Sleep problems and restlessness: Some users report feeling wired or having difficulty sleeping
- Liver concerns: While not a major issue at typical doses, animal studies have raised some concerns about liver effects at high doses
Drug Interactions
Ginkgo interacts with numerous medications, creating potentially dangerous situations:
Blood Thinners and Antiplatelet Drugs
Ginkgo frequently interacts with antiplatelet drugs and anticoagulants, with clopidogrel and aspirin showing the highest prevalence rates (2.61% each). A study of Veterans Administration patients found that taking ginkgo with warfarin increased bleeding risk by 38% (hazard ratio of 1.38).
Antidepressants
The combination of ginkgo with SSRI or SNRI antidepressants can lead to hemorrhagic complications (accounting for 27.45% of complications in one study) and potentially life-threatening serotonin syndrome.
Diabetes Medications
The research on ginkgo’s effects on blood sugar is conflicting. Some studies suggest ginkgo might increase blood sugar levels and reduce the effectiveness of diabetes medications, while others show it may help improve blood glucose control when combined with metformin.
Seizure Medications
Ginkgo can induce liver enzymes that break down anti-seizure medications faster, reducing their effectiveness and potentially leading to breakthrough seizures.
Surgery
Ginkgo should be discontinued at least two weeks before any surgical procedure due to increased bleeding risk. Cases of post-surgical bleeding complications have been documented, including persistent bleeding after hip arthroplasty that stopped only six weeks after ginkgo was discontinued.
Who Should Avoid Ginkgo Biloba
Pregnant and Breastfeeding Women
The safety of ginkgo during pregnancy and breastfeeding is unknown. Animal studies have shown concerning effects, including decreased fetal weight and evidence of intrauterine growth retardation. The anti-platelet properties could also prolong bleeding time during labor.
People with Bleeding Disorders
If you have any bleeding disorder, ginkgo is off-limits. The herb might make bleeding disorders worse and should not be used.
Individuals with Epilepsy
Ginkgo might cause seizures and should not be used by anyone who has ever had a seizure. The risk is particularly high for those already taking anti-seizure medications.
Children and Adolescents
There is insufficient evidence to support the use of ginkgo in children. The limited research available doesn’t justify the risks given the lack of solid safety data for pediatric use.
People Scheduled for Surgery
Stop taking ginkgo at least two weeks before any planned surgery to reduce bleeding risk.
Efficacy Considerations
It’s critically important to understand that despite ginkgo’s widespread popularity and marketing claims, the scientific evidence for its effectiveness remains controversial and inconsistent across different conditions.
Mixed Evidence for Cognitive Benefits
Research on ginkgo’s effectiveness shows conflicting results. Some systematic reviews and meta-analyses have found modest benefits for cognition in patients with dementia, particularly when using standardized EGb 761 extract at 240 mg doses for 22-26 weeks. These studies showed that ginkgo could stabilize or slow decline in cognition, function, behavior, and global change, especially for patients with neuropsychiatric symptoms.
However, major prevention trials have been disappointing. The large Ginkgo Evaluation of Memory (GEM) study involving thousands of older adults found no significant benefit for preventing dementia or improving memory in healthy individuals over 75 years of age. A meta-analysis of two trials involving 5,889 participants showed no significant difference in dementia rates between ginkgo and placebo.
What Health Authorities Say
The National Center for Complementary and Integrative Health has stated that ginkgo has not been shown to be effective for many of the conditions for which it has been studied. This is a sobering assessment from a respected federal health agency.
Recent real-world data from Germany (published December 2024) analyzing over 10 years of patient records did find an association between ginkgo prescriptions and slower progression of dementia severity, suggesting potential benefits in actual clinical practice that may differ from controlled trial settings. However, more research is needed to confirm these observational findings.
The Bottom Line on Effectiveness
While some studies suggest potential benefits for certain patients with dementia, especially at higher doses (240 mg), the evidence doesn’t support ginkgo’s use for preventing cognitive decline in healthy individuals or for improving memory in people without cognitive impairment. This means many people may be taking ginkgo and experiencing potential side effects for benefits that may never materialize.
Safe Use Guidelines to Minimize Ginkgo Biloba Side Effects
If you decide to use ginkgo biloba despite the potential ginkgo biloba side effects:
Start with lower doses (40-60 mg daily) to assess tolerance before increasing to standard doses of 120-240 mg daily.
Take with food to minimize digestive side effects.
Inform your healthcare provider about all medications and supplements you’re taking, as ginkgo interacts with many common drugs.
Monitor for ginkgo biloba side effects, especially unusual bleeding, bruising, headaches, or dizziness.
Stop immediately if you experience signs of an allergic reaction, unusual bleeding, seizure activity, severe chest pain, or other serious symptoms.
Quality matters: Look for standardized extracts containing 24% flavone glycosides and 6% terpene lactones from reputable brands with third-party testing.
The Bottom Line on Ginkgo Biloba Side Effects
Ginkgo biloba is generally safe for most healthy adults when used appropriately, but it’s not without risks. Common ginkgo biloba side effects like stomach upset, headaches, and dizziness are usually mild and temporary. However, the more serious ginkgo biloba side effects—particularly increased bleeding, seizure potential in susceptible individuals, and numerous drug interactions—require careful consideration.
Given the mixed evidence for effectiveness and the potential for serious ginkgo biloba side effects, anyone considering ginkgo should consult with a healthcare provider first, especially if taking other medications or managing health conditions. Understanding these ginkgo biloba side effects is crucial because the risks may not outweigh the uncertain benefits for many people.
Sources:
National Center for Complementary and Integrative Health. Ginkgo. https://www.nccih.nih.gov/health/ginkgo
Mayo Clinic. Ginkgo. https://www.mayoclinic.org/drugs-supplements-ginkgo/art-20362032
Bent S, et al. Spontaneous bleeding associated with ginkgo biloba: A case report and systematic review of the literature. J Gen Intern Med. 2005;20(7):657-61.
Mai NTQ, et al. Impact of Ginkgo biloba drug interactions on bleeding risk and coagulation profiles: A comprehensive analysis. PLoS One. 2025 Apr 8;20(4):e0321804.
Granger AS. Ginkgo biloba precipitating epileptic seizures. Age and Ageing. 2001;30(6):523-525.
About the Author
Steph Swarts, RMT, CNP
Steph Swarts is a registered massage therapist and certified naturopathy practitioner with 17+ years of clinical experience helping clients optimize their health through evidence-based supplementation and holistic wellness strategies.
Professional Credentials:
- Registered Massage Therapist (RMT) – Licensed in Ontario, Canada
- Certified Naturopathic Practitioner (CNP)
- Raindrop Technique Practitioner (RTP)
- 17+ years in clinical practice
- Specialized training in Prenatal Massage Therapy
Clinical Expertise:
“As a healthcare professional with naturopathic training, I evaluate supplements using the same rigorous standards I apply in client care. My recommendations prioritize:
✅ Safety: Thorough evaluation of quality and purity
✅ Evidence: Backed by peer-reviewed research
✅ Clinical relevance: Real-world effectiveness for performance and recovery
✅ Professional standards: Third-party testing and manufacturing quality
Over 17+ years, I’ve guided hundreds of clients through their health journey, injury recovery, and overall wellness. Every recommendation reflects my professional commitment to evidence-based natural health.
Professional Memberships:
- Registered Massage Therapist with CMTO
- Member of RMTAO
- Certified Naturopathy Practitioner with NCCAP, CPD, and CMA
- Raindrop Technique Practitioner with Institute Of Energy Wellness Studies
📧 Contact: [email protected]
🌐 Website: www.stephswarts.com
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Professional Disclaimer: Information provided is for educational purposes based on clinical expertise and current research. This does not replace individualized medical advice. Consult your healthcare provider before starting any supplement regimen, especially if you have pre-existing conditions or take medications.
