Ginkgo Biloba and Blood Thinners: What You Need to Know About Bleeding Risk

If you're taking a blood thinner like warfarin, aspirin, or clopidogrel, and you're also using Ginkgo biloba for memory or circulation, you could be putting yourself at risk - even if you feel fine. This isn't speculation. It's documented in hospital reports, clinical studies, and poison control logs. The problem isn't always obvious. No warning lights flash. No symptoms show up until it's too late.

What Ginkgo Biloba Actually Does

Ginkgo biloba comes from the leaves of the Ginkgo tree, one of the oldest living tree species on Earth. It's been used in traditional Chinese medicine for centuries. Today, it's sold as a supplement to improve memory, reduce dizziness, or boost blood flow. The most common extracts contain 24% flavonoid glycosides and 6% terpene lactones, with typical doses ranging from 120 to 240 mg per day. Over 1.5 million Americans take it regularly, spending about $100 million a year on it.

But here’s the catch: Ginkgo biloba interferes with how your blood clots. It doesn’t thin your blood like warfarin does - it changes the way platelets stick together. That means if you cut yourself, or worse, if you have a minor internal bleed, your body struggles to stop it. This isn’t a theory. It’s a pattern seen in real patients.

The Real Risk: When Ginkgo Meets Blood Thinners

The danger isn’t just with prescription drugs. It’s also with everyday pain relievers you might not think twice about.

Take aspirin. Many people take 80 mg daily for heart health. Add Ginkgo biloba on top, and suddenly your risk of bleeding spikes. One case report described a man who developed spontaneous bleeding in his right eye after just one week of taking Ginkgo with low-dose aspirin. Another case involved a young woman with no other medications - just long-term Ginkgo use - who suffered a life-threatening brain hemorrhage.

Warfarin (Coumadin, Jantoven) is especially risky. Studies show Ginkgo can push INR levels - a key measure of blood clotting time - into dangerous territory. One patient’s INR jumped from 2.5 to 5.8 after starting Ginkgo. That’s not just elevated; it’s a red flag for internal bleeding.

Even over-the-counter drugs like ibuprofen (Advil, Motrin IB), celecoxib (Celebrex), and naproxen can become dangerous when mixed with Ginkgo. So can medications like nifedipine (for high blood pressure) and omeprazole (for acid reflux). The NIH study in 2024 found that combinations of Ginkgo with these drugs led to abnormal coagulation test results - even when no bleeding was reported. That’s the scary part: the warning signs show up in lab tests before you feel anything.

Contradictory Studies - What Should You Believe?

You might have heard that Ginkgo doesn’t really affect bleeding. One 2023 study in PLOS ONE tested 29 different blood clotting parameters after giving people a standard Ginkgo extract (EGb 761). None showed inhibition of clotting. So does that mean it’s safe?

No. That study looked at controlled lab conditions in healthy volunteers. Real life isn’t like that. Most people taking Ginkgo are older, on multiple medications, or have underlying conditions like high blood pressure or diabetes. The same study found a clear link between Ginkgo use and actual bleeding events - especially when combined with clopidogrel, aspirin, or loxoprofen. The odds of bleeding went up by 8%, and abnormal coagulation results jumped by nearly 50%.

Meanwhile, case reports keep coming in. The Consumer Medication Safety Institute recorded multiple incidents of unexplained bleeding in people using Ginkgo alongside anticoagulants. These aren’t outliers. They’re signals.

The truth? The science isn’t black and white. But when you’re dealing with something as serious as internal bleeding, you don’t wait for perfect proof. You act on what’s already known.

Who Should Avoid Ginkgo Altogether?

Some people should never take Ginkgo biloba - not even for a day.

• People on blood thinners: Warfarin, aspirin, clopidogrel, ticagrelor, rivaroxaban - any of these? Skip Ginkgo.
• Those with bleeding disorders: Hemophilia, von Willebrand disease, or a history of easy bruising or nosebleeds? Ginkgo makes it worse.
• Older adults: Aging bodies process drugs differently. The risk of bleeding increases with age, and Ginkgo adds to that.
• Pregnant women: Ginkgo can affect uterine blood flow. There’s no safe dose established.
• People preparing for surgery: The American Society of Anesthesiologists says stop Ginkgo 2 to 3 weeks before any planned procedure. That’s not a suggestion. It’s a safety rule.

And don’t forget the seeds. Fresh or roasted Ginkgo seeds are toxic. They can cause seizures, vomiting, and even death. Stick to standardized leaf extracts - and even then, proceed with caution.

What About Other Supplements?

Ginkgo isn’t the only herbal supplement that plays games with your blood. Garlic, ginger, ginseng, and fish oil all have similar effects. But Ginkgo is uniquely dangerous because it’s so widely used - and so poorly understood.

Many people think “natural” means “safe.” That’s a myth. Natural doesn’t mean harmless. It just means it’s not patented. That means less regulation. The FDA doesn’t approve supplements before they hit shelves. Manufacturers are responsible for safety - but they’re not required to prove it.

That’s why product quality varies wildly. One bottle of Ginkgo might have the right dose. Another might be diluted, contaminated, or contain undisclosed ingredients. There’s no way to know unless you buy from a trusted, third-party tested brand. But even then, the interaction risk remains.

What Should You Do?

If you’re taking a blood thinner and you’re also using Ginkgo biloba, here’s what to do - right now:

1. Stop taking Ginkgo. Don’t wait. Don’t “try it for a few more days.”
2. Talk to your doctor or pharmacist. Bring your full list of supplements and medications. Don’t assume they know what you’re taking. Most doctors don’t ask about herbs unless you bring it up.
3. Get a coagulation test. If you’ve been on Ginkgo for more than a week while on blood thinners, ask for an INR or PT/PTT test. It’s quick, cheap, and could save your life.
4. Wait 2 to 3 weeks before any surgery. Even if your dentist says it’s “just a cleaning,” they need to know. Minor procedures can still cause bleeding complications.
5. Don’t restart without approval. Even if your doctor says it’s okay, they’ll likely want you off it for longer than you think.

There’s no proven benefit of Ginkgo biloba that outweighs the bleeding risk when you’re on anticoagulants. Not for memory. Not for circulation. Not for tinnitus. The science just doesn’t support it.

What Are the Alternatives?

If you’re taking Ginkgo for memory or brain health, there are safer options. Regular exercise, good sleep, and managing blood pressure and cholesterol do more for cognitive function than any supplement. Omega-3s from fish oil (if you’re not on blood thinners) or phosphatidylserine have more evidence behind them - and far fewer risks.

If you’re using Ginkgo for circulation or leg pain, talk to your doctor about approved treatments like pentoxifylline or supervised exercise programs. These work. And they’re monitored.

There’s no shortcut to health. Supplements aren’t magic pills. They’re drugs with side effects - and Ginkgo biloba is one of the most dangerous ones you can mix with blood thinners.

Final Warning

You might think, “I’ve been taking Ginkgo for years and nothing happened.” That’s not proof it’s safe. It’s just luck. Bleeding events can happen suddenly - after a fall, a dental procedure, or even a cough. There’s no warning. No pain. Just internal bleeding that can turn fatal.

One study found that patients who took Ginkgo with warfarin were more likely to be hospitalized for bleeding than those who didn’t. The risk wasn’t huge - but it was real. And when you’re talking about brain bleeds or eye hemorrhages, “not huge” doesn’t matter.

If you’re on blood thinners, Ginkgo biloba is not worth the risk. Period.