Understanding Ginkgo Biloba and Its Associated Risks
Ginkgo biloba is an herbal supplement derived from one of the oldest living tree species. Extracts from its leaves are commonly marketed to improve memory and circulation [1.2.1]. While some users tolerate it well, it is not without significant drawbacks. Raw or roasted ginkgo seeds are poisonous and can cause serious side effects, including seizures or even death, and should not be consumed [1.4.2, 1.4.3]. Even the standardized leaf extract carries risks that range from minor discomforts to severe medical events. It is essential for consumers to be aware of these potential negatives before starting supplementation.
Common and Minor Side Effects
Though often considered mild, the frequent side effects of ginkgo biloba can be disruptive. These commonly include:
- Headaches [1.2.3]
- Dizziness [1.2.5]
- Gastrointestinal issues such as nausea, diarrhea, constipation, and general stomach upset [1.2.2, 1.2.4]
- Heart palpitations, which can feel like a rapid, pounding, or irregular heartbeat [1.2.4]
- Allergic skin reactions, like rashes or itching [1.7.2]
While these symptoms may seem minor, their persistence can impact daily life and should be monitored. If they continue or worsen, consulting a healthcare provider is recommended [1.2.7].
Serious Health Concerns and Contraindications
Beyond minor side effects, there are more severe negatives associated with ginkgo biloba use. These risks warrant careful consideration, especially for individuals with pre-existing health conditions.
The Most Significant Negative: Increased Bleeding Risk
The most well-documented and serious negative of ginkgo biloba is its effect on blood clotting. Ginkgo can slow blood clotting, which significantly increases the risk of bleeding [1.5.3]. This is particularly dangerous for certain individuals:
- People with bleeding disorders: Those with conditions like hemophilia should avoid ginkgo as it can worsen the disorder [1.4.2].
- Patients undergoing surgery: It is recommended to stop taking ginkgo at least two weeks before a scheduled surgery to prevent excessive bleeding during and after the procedure [1.4.2, 1.4.3].
- Individuals on blood-thinning medications: Combining ginkgo with anticoagulants or antiplatelet drugs dramatically elevates bleeding risk [1.5.3].
Case reports have documented serious bleeding events, including intracranial (brain) bleeding and spontaneous hyphema (bleeding in the eye), associated with ginkgo use [1.5.1, 1.5.2].
Neurological and Other Major Risks
Ginkgo has been linked to several other serious health issues:
- Seizures: Ginkgo may increase the risk of seizures, especially in people with a history of epilepsy. It can also reduce the effectiveness of anticonvulsant medications [1.4.2, 1.4.7]. The ginkgotoxin found in ginkgo seeds, and to a lesser extent in leaves, is known to cause seizures [1.7.4].
- Allergic Reactions: Severe allergic reactions are possible, including hives, swelling of the face, lips, or throat, and difficulty breathing [1.2.2]. People with allergies to poison ivy, mango rind, or cashew shell oil may have a cross-reaction to ginkgo [1.4.2].
- Toxicity Concerns: While long-term use of standardized extracts appears generally safe in some studies, others raise concerns [1.6.1]. The International Agency for Research on Cancer has classified ginkgo biloba extract as a possible human carcinogen (Group 2B) based on animal studies that showed an increased incidence of liver and thyroid cancers in rodents [1.6.3, 1.6.4]. Unprocessed parts of the plant, especially fresh seeds, are toxic and can be fatal [1.6.2].
Who Should Avoid Ginkgo Biloba?
Certain populations should not use ginkgo biloba due to the potential for serious harm:
- Pregnant or breastfeeding women [1.4.2]
- Children (unless specifically advised by a doctor) [1.4.2]
- Individuals with epilepsy or a history of seizures [1.4.4]
- People with bleeding disorders [1.4.2]
- Those scheduled for surgery [1.4.1]
- Individuals with diabetes should monitor blood sugar closely as ginkgo might interfere with its management [1.4.2].
Critical Drug Interactions
Ginkgo biloba interacts with a wide array of medications, altering their effectiveness and increasing the risk of adverse effects. This is one of its most significant negatives from a pharmacological standpoint.
| Medication Class/Drug | Nature of Interaction with Ginkgo Biloba |
|---|---|
| Anticoagulants/Antiplatelets (e.g., Warfarin, Aspirin, Clopidogrel) | Significantly increases the risk of bruising and serious bleeding [1.3.1, 1.5.3]. |
| NSAIDs (e.g., Ibuprofen, Naproxen) | Combining with ginkgo can heighten the risk of bleeding [1.3.1, 1.4.6]. |
| Anticonvulsants (Seizure Medications) | Ginkgo may lower the seizure threshold and decrease the effectiveness of these drugs, increasing seizure risk [1.4.2]. |
| Antidepressants (e.g., Fluoxetine, Trazodone) | May reduce the efficacy of some antidepressants. Can lead to coma when combined with trazodone [1.3.1, 1.3.4]. |
| Diabetes Medications | Ginkgo can affect blood sugar levels, potentially interfering with the management of diabetes [1.3.1, 1.4.6]. |
| Alprazolam (Xanax) | Taking ginkgo might reduce the effectiveness of this anti-anxiety medication [1.3.1]. |
| Certain Statins (e.g., Atorvastatin, Simvastatin) | Ginkgo may reduce the effectiveness of these cholesterol-lowering drugs [1.3.1]. |
| Proton Pump Inhibitors (e.g., Omeprazole) | Ginkgo may decrease the effectiveness of omeprazole by increasing how fast the liver breaks it down [1.4.2]. |
Conclusion
While ginkgo biloba is a popular herbal supplement, the negatives are substantial and cannot be overlooked. The primary concern is the increased risk of bleeding, which is amplified when taken with other blood-thinning medications or by individuals with bleeding disorders [1.5.1, 1.5.3]. Furthermore, its potential to cause seizures, trigger allergic reactions, and interact with a wide range of common prescription drugs makes it a supplement that requires extreme caution [1.4.2, 1.3.1]. The unproven benefits for conditions like dementia and tinnitus often do not outweigh these documented risks [1.2.3]. Before taking ginkgo biloba, it is imperative to consult with a healthcare provider to discuss your medical history and current medications to avoid potentially dangerous outcomes.
Authoritative Link: For more detailed information on safety and side effects, consult the National Center for Complementary and Integrative Health (NCCIH) page on Ginkgo: https://www.nccih.nih.gov/health/ginkgo
