Ginkgo Biloba and Blood Thinners: What You Need to Know Before Taking Both

Millions of people take Ginkgo biloba every year to help with memory, focus, or circulation. It’s one of the most popular herbal supplements out there. But if you’re also on a blood thinner-like warfarin, aspirin, or clopidogrel-you need to stop and think. Mixing Ginkgo biloba with blood thinners isn’t a simple yes-or-no question. Some experts say it’s risky. Others say the evidence doesn’t back that up. So what’s the real story?

What Exactly Is Ginkgo Biloba?

Ginkgo biloba comes from the leaves of the Ginkgo tree, one of the oldest tree species on Earth, dating back over 270 million years. In traditional Chinese medicine, it was used for breathing issues and circulation. Today, it’s sold as a standardized extract called EGb 761 a specific 50:1 leaf extract containing 24% flavonol glycosides and 6% terpene lactones. This is the version most studies use, and it’s the one you’ll find in most reputable supplements. About 70% of global Ginkgo sales are this exact formula. It’s not just any leaf powder-it’s a precise, tested extract.

It’s commonly used for memory support, especially in older adults. But it’s also believed to improve blood flow by relaxing blood vessels and reducing platelet stickiness. That’s where the problem starts. If you’re already on a medication that thins your blood, adding something that makes platelets less likely to clump could be dangerous.

How Blood Thinners Work

Blood thinners aren’t one thing. They fall into two main groups:

• Anticoagulants like warfarin (Coumadin), apixaban (Eliquis), and rivaroxaban (Xarelto). These work by slowing down your body’s clotting process, often by blocking vitamin K or specific clotting factors.
• Antiplatelets like aspirin, clopidogrel (Plavix), and ticagrelor (Brilinta). These stop platelets from sticking together, which is the first step in forming a clot.

Both types reduce the risk of strokes and heart attacks. But they also increase your chance of bleeding. Even a small cut can take longer to stop. A bump on the head could lead to internal bleeding. That’s why doctors are so careful when prescribing them.

The Theory: Why Ginkgo Might Interact

Ginkgo biloba contains compounds that affect platelets. Research from 2011 in Frontiers in Pharmacology showed it can block platelet-derived growth factors and reduce thrombin-induced platelet activation. In plain terms: it makes platelets less sticky. That sounds good-until you’re already on a drug that does the same thing.

There’s another angle. Ginkgo may interfere with the liver enzyme CYP2C9, which breaks down warfarin. If this enzyme slows down, warfarin builds up in your blood. That could push your INR (a blood test that measures clotting time) too high, increasing bleeding risk.

That’s the theory. But theory doesn’t always match real life.

The Evidence: What Studies Actually Show

Here’s the messy part. Controlled studies don’t always agree with case reports.

A 2012 study in Thrombosis and Haemostasis gave people Ginkgo and aspirin together. No increase in bleeding. No change in clotting time. Nothing alarming.

But then you look at case reports. Between 2008 and 2020, the FDA received 18 reports of bleeding events linked to Ginkgo. One involved a man who had a brain bleed after taking Ginkgo with warfarin. Another involved a woman who bled heavily after surgery while still using Ginkgo. These are rare, but they happened.

Here’s the key insight: almost all the serious cases involved non-standardized Ginkgo products-cheap supplements with unknown strength, inconsistent ingredients, or even contamination. The studies that found no risk? They used the clean, well-tested EGb 761 formula.

That’s why experts are split. The Mayo Clinic warns patients to avoid Ginkgo with blood thinners. GoodRx calls warfarin a "high-risk" interaction. But the PubMed review by Izzo et al. (2008) found no convincing evidence that Ginkgo significantly affects clotting when used with aspirin or warfarin.

What Do Doctors Actually Recommend?

Most doctors don’t have a clear answer. So they go with caution.

• Mayo Clinic: Says Ginkgo may raise bleeding risk with aspirin, clopidogrel, or warfarin. Advises caution.
• Cleveland Clinic: Lists blood thinners as a contraindication-meaning don’t take it if you’re on one.
• Dr. Michael Murray: Recommends stopping Ginkgo 36 hours before surgery.
• Dr. Tieraona Low Dog: Says stop it 2 weeks before surgery.
• American Society of Anesthesiologists: Recommends stopping all herbal supplements 2 weeks before surgery, including Ginkgo.

Pharmacists are even more cautious. A 2022 survey found that 78% of pharmacists routinely warn patients about Ginkgo-blood thinner combinations. Over half recommend stopping it before any procedure.

Electronic health records now flag these interactions. Epic’s system alerts doctors if someone is on warfarin and Ginkgo. Cerner alerts for all anticoagulants. That’s not a coincidence. Hospitals are seeing the risk, even if the science isn’t settled.

What About Other Supplements?

Ginkgo isn’t alone. Garlic, danshen, ginger, and evening primrose oil also affect blood clotting. If you’re on a blood thinner, you need to think about your whole supplement list-not just one thing.

A 2020 study in PLOS ONE found that 21% of people on blood thinners were also taking herbal supplements. Nearly half of those were at risk for dangerous interactions. That’s not small. That’s a lot of people flying under the radar.

What Should You Do?

You don’t need to panic. But you do need to act.

1. Check your labels. If your Ginkgo supplement doesn’t say "EGb 761" or "standardized extract," it’s not the same as what was studied. Avoid it.
2. Don’t start Ginkgo without telling your doctor. Even if you’re feeling fine, your blood thinner levels could shift. A simple INR test can catch problems early.
3. Stop Ginkgo before surgery. Whether it’s a dental extraction or knee replacement, stop it at least 2 weeks before. Better safe than sorry.
4. Track your symptoms. Unexplained bruising, nosebleeds, blood in urine or stool? These aren’t normal. Call your doctor.
5. Use one pharmacy. If you get prescriptions and supplements from different places, your pharmacist won’t see the full picture. One pharmacy means one full record.

There’s no magic number. No guaranteed safe dose. The safest move is to assume interaction is possible until proven otherwise.

Final Thought: Trust, But Verify

Ginkgo biloba has been used safely by millions. But when you add a blood thinner into the mix, you’re playing with fire-even if the flame is small. The science is messy. The advice is conflicting. But your body doesn’t care about studies. It reacts to what’s in your bloodstream.

If you’re thinking about starting Ginkgo, talk to your doctor first. If you’re already taking it, don’t quit cold turkey-ask how to taper safely. And if you’re on warfarin? That’s the one to be extra careful with. It’s the most sensitive. It’s the one that’s hardest to balance.

Your health isn’t about following a trend. It’s about knowing what’s in your body-and who’s watching over it.