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 might be at risk for something serious-internal bleeding. It’s not a myth. It’s not a scare tactic. It’s a documented, real danger that shows up in emergency rooms and operating rooms across the UK and the US. And most people have no idea it’s even a possibility.

What Ginkgo Biloba Actually Does

Ginkgo biloba comes from the leaves of the Ginkgo tree, one of the oldest living tree species on Earth. For decades, it’s been sold as a natural way to boost memory, improve circulation, and even fight dementia. The standard extract used in supplements contains 24% flavonoid glycosides and 6% terpene lactones. Most people take 120-240 mg per day. Over 1.5 million Americans use it regularly. In the UK, it’s widely available in pharmacies and health stores without a prescription.

But here’s the catch: Ginkgo biloba interferes with blood clotting. It doesn’t thin your blood like warfarin does. Instead, it slows down the way platelets stick together. That might sound harmless-until you cut yourself, fall, or need surgery. Then, your body can’t form clots fast enough. And that’s when things go wrong.

The Real Risk: Bleeding When You Least Expect It

You don’t need to be on multiple blood thinners to be in danger. One case reported by the Consumer Medication Safety Institute involved a man who started taking Ginkgo biloba for memory and low-dose aspirin (80 mg) for heart health. Within a week, he suffered spontaneous bleeding in his right eye. No trauma. No warning. Just bleeding-because the two substances together overwhelmed his body’s ability to stop it.

Another case involved a young woman with no other medications. She’d been taking Ginkgo biloba for years. Then, she had a sudden brain bleed. No trauma. No stroke. Just Ginkgo. The same thing happened to others. In fact, a 2023 study in PLOS ONE found that people taking Ginkgo biloba along with common blood thinners had a 49% higher chance of abnormal blood clotting tests-and an 8% higher chance of actual bleeding events.

It’s not just aspirin or warfarin. Ginkgo interacts dangerously with:

• Clopidogrel (Plavix) - used after heart attacks or stents
• Warfarin (Coumadin, Jantoven) - the classic blood thinner
• Ibuprofen (Advil, Motrin) - common OTC painkiller
• Celecoxib (Celebrex) - arthritis medication
• Nifedipine (Procardia) - blood pressure drug
• Omeprazole (Prilosec) - acid reflux pill

Even if you’re only on one of these, Ginkgo can push you over the edge. The problem isn’t always the dose. It’s the combination.

Why the Confusion? Contradictory Studies

You might have heard that Ginkgo doesn’t really affect bleeding. That’s because some studies say it doesn’t. A 2023 trial tested EGb 761-a high-quality Ginkgo extract-on 29 different blood clotting markers. None showed inhibition. So why do we still see bleeding cases?

The answer is simple: real people aren’t lab subjects. In controlled trials, participants are healthy, monitored, and take one supplement. In real life, people take Ginkgo with five other meds, have underlying conditions, or take inconsistent doses. One study found that while bleeding incidents didn’t always spike, abnormal blood test results did-meaning your body is struggling, even if you don’t feel it.

Also, not all Ginkgo supplements are the same. The FDA doesn’t regulate herbal products like prescription drugs. Two bottles labeled “Ginkgo biloba 120 mg” can have wildly different amounts of active ingredients. One might be pure. Another might be diluted-or even contaminated. That’s why case reports keep popping up. The product you buy might be riskier than you think.

When Surgery Is Involved: The 2-Week Rule

If you’re scheduled for any surgery-whether it’s a knee replacement, a colonoscopy, or even a simple tooth extraction-your surgeon needs to know about every supplement you take. The American Society of Anesthesiologists says stop Ginkgo biloba 2 to 3 weeks before surgery. Why so long?

Because Ginkgo’s effects linger. It doesn’t just leave your system in a day. It changes how your platelets behave for weeks. A 2023 study suggested 36 hours might be enough, but that’s based on pharmacokinetics alone. Real-world bleeding risk doesn’t care about half-lives. It cares about whether your blood can clot when you’re cut open. That’s why doctors stick with the 2-3 week window. It’s the only safe margin.

Don’t assume your doctor knows you’re taking it. Most don’t ask. It’s your job to speak up. Bring your pill bottles. List every supplement. Even if you think it’s “just herbal.”

Who Should Avoid Ginkgo Altogether?

Some people shouldn’t take Ginkgo biloba at all-not even for a day.

• People on blood thinners - even low-dose aspirin
• Those with bleeding disorders - like hemophilia or von Willebrand disease
• Pregnant or breastfeeding women - risk of fetal bleeding
• People with epilepsy - Ginkgo may lower seizure threshold
• Anyone over 65 - older adults have slower clotting and more medication interactions

Mayo Clinic explicitly warns these groups to avoid Ginkgo. And they’re not being overly cautious. They’ve seen the outcomes.

What About Other Supplements?

Ginkgo isn’t alone. Garlic, ginger, ginseng, and fish oil also interfere with clotting. But Ginkgo is one of the most common ones people take without realizing the danger. And unlike prescription drugs, you won’t find warnings on the bottle. No red flags. No asterisks. Just a label that says “supports memory.”

Here’s the hard truth: if you’re taking any supplement that claims to “improve circulation” or “boost brain function,” assume it might affect your blood. Always check with your pharmacist before adding anything new.

What to Do Right Now

If you’re taking a blood thinner and Ginkgo biloba, here’s what you need to do:

1. Stop taking Ginkgo immediately-don’t wait. Even if you feel fine.
2. Call your doctor or pharmacist-tell them exactly what you’ve been taking and for how long.
3. Don’t restart without approval-even if you read online that it’s “safe.”
4. Check your other supplements-fish oil, garlic, turmeric? They’re risky too.
5. Bring all your meds to every appointment-including vitamins and herbal teas.

There’s no magic dose of Ginkgo that’s “safe” with blood thinners. The risk isn’t linear. It’s cumulative. One pill might not do it. But two weeks of taking it with aspirin? That’s enough to cause a bleed.

Final Reality Check

Ginkgo biloba isn’t evil. It’s not a poison. But it’s not harmless, either. It’s a powerful plant extract that changes how your body works. And when you mix it with medications designed to control life-or-death processes like blood clotting, you’re playing with fire.

There’s no strong evidence that Ginkgo improves memory in healthy people. But there’s plenty of evidence that it can cause bleeding-sometimes silently, sometimes catastrophically. If you’re on blood thinners, the safest choice isn’t to find the “right dose.” It’s to skip it entirely.

Your health isn’t worth the gamble. Not when the stakes are internal bleeding, stroke, or death.