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

Millions of people take Ginkgo biloba every year hoping to boost memory, improve circulation, or just feel more alert. But if you’re also on a blood thinner-like warfarin, aspirin, or clopidogrel-you could be putting yourself at risk. The problem isn’t just theoretical. Real people have bled internally after mixing the two. And while some studies say it’s safe, others warn of serious, even deadly, outcomes. So what’s the truth? And what should you actually do?

What is Ginkgo Biloba, Really?

Ginkgo biloba comes from the leaves of the Ginkgo tree, one of the oldest living tree species on Earth. It’s been used in Chinese medicine for over 1,000 years. Today, most supplements use a standardized extract called EGb 761, which contains 24% flavonol glycosides and 6% terpene lactones. This specific mix is what most research studies use-and it’s the version you’re most likely to find on store shelves. About 12 million Americans take it annually, mostly for brain health or circulation.

But here’s the catch: Ginkgo doesn’t just help blood flow. It also changes how your blood clots. It interferes with platelets, the tiny cells that stick together to form clots. That’s why it’s linked to bleeding risks, especially when combined with medications designed to thin your blood.

How Blood Thinners Work (And Why Ginkgo Might Make Them Stronger)

Blood thinners fall into two main groups: antiplatelets and anticoagulants. Antiplatelets like aspirin and clopidogrel stop platelets from clumping. Anticoagulants like warfarin and DOACs (rivaroxaban, apixaban) slow down the chemical process that forms clots. Ginkgo biloba affects both systems.

Studies show Ginkgo can block platelet-activating signals and may interfere with the liver enzyme CYP2C9, which breaks down warfarin. That means warfarin could stay in your system longer, increasing your risk of bleeding. It’s not a guaranteed effect-but it’s enough of a possibility that doctors take it seriously.

The data isn’t clean. Some controlled trials found no significant interaction between Ginkgo and aspirin or warfarin. But case reports tell a different story. There are documented cases of brain bleeds, nosebleeds that wouldn’t stop, and internal bleeding after surgery-all in people taking Ginkgo along with blood thinners. The key difference? Most of the serious cases involved non-standardized Ginkgo products. That means the dose, purity, and ingredients varied wildly. EGb 761, the standardized form, appears safer. But most supplements sold in the U.S. aren’t tested to that standard.

The Real Risk: When It Turns Dangerous

Let’s be clear: you won’t bleed out just because you took a Ginkgo pill with your aspirin. But the risk isn’t zero. And it gets worse under certain conditions.

• Before surgery: Even minor procedures like dental work or a colonoscopy can trigger dangerous bleeding if you’re on both.
• After a fall or injury: A bump on the head that would normally cause a bruise could lead to a brain hemorrhage.
• With other supplements: Garlic, ginger, fish oil, danshen, and even high-dose vitamin E can add to the risk.

According to the FDA, between 2008 and 2020, they received 18 reports of bleeding events possibly linked to Ginkgo. Causality wasn’t proven in any of them-but that’s because proving it’s hard. You don’t need perfect proof to stop taking something risky. You just need enough warning signs.

What the Experts Say (And Why They Disagree)

There’s a split among medical authorities. The Mayo Clinic, Cleveland Clinic, and GoodRx all warn against combining Ginkgo with blood thinners. GoodRx lists warfarin as a "high-risk" interaction and says to avoid it entirely. The American Society of Anesthesiologists recommends stopping Ginkgo two weeks before any surgery.

But other experts, like those behind the 2008 PubMed review, argue that the evidence doesn’t support panic. They point to well-designed studies showing no significant change in bleeding time or INR levels when Ginkgo is taken with warfarin. The American Society of Health-System Pharmacists calls the risk "theoretical." The American College of Chest Physicians says routine discontinuation isn’t needed.

So who’s right? The answer might be: both. The standardized extract (EGb 761) likely poses little risk in healthy people. But most people aren’t taking EGb 761. They’re taking whatever’s cheapest on the shelf. And if you’re older, have liver problems, or are on multiple medications, your body handles things differently. That’s where the danger hides.

What You Should Do Right Now

If you’re taking a blood thinner and thinking about starting Ginkgo biloba-stop. Don’t take it. Not until you talk to your doctor or pharmacist.

If you’re already taking both, don’t panic. But do these three things:

1. Check your labels. Look at your Ginkgo bottle. Does it say "standardized to EGb 761"? If not, you don’t know what you’re getting.
2. Tell your prescriber. Bring your supplement list to every appointment. Not just your pills-your herbs, vitamins, and teas too.
3. Stop Ginkgo before any procedure. Whether it’s a dental cleaning or a knee replacement, stop taking it at least two weeks beforehand. Some experts say 36 hours is enough. But when it comes to bleeding risk, better safe than sorry.

Pharmacists are your best allies here. A 2022 survey found that 78% of pharmacists routinely warn patients about Ginkgo-blood thinner interactions. They see the mix every day. Ask them.

What About Natural Alternatives?

If you’re taking Ginkgo for memory or focus, you’re not alone. But there are safer options. Omega-3s from fish oil can support brain health without the same bleeding risk (though they still interact with blood thinners, so talk to your doctor). Regular physical activity, sleep, and managing blood pressure do more for cognitive function than any supplement. If you’re worried about circulation, walking 30 minutes a day is proven, free, and doesn’t come with a warning label.

And if you’re using Ginkgo for tinnitus or vertigo? The evidence for those uses is weak. You’re not missing out on a miracle cure. You’re risking a bleed.

Final Reality Check

The supplement industry isn’t regulated like pharmaceuticals. A bottle of Ginkgo can have anywhere from 10% to 100% of the labeled amount of active ingredients. Some contain fillers, heavy metals, or even undisclosed drugs. That’s why standardized extracts like EGb 761 are the only ones trusted in clinical trials. But they’re also the most expensive.

If you’re on a blood thinner, you’re already managing a delicate balance. Adding an unregulated herb into the mix is like playing Russian roulette with your health. The odds might be low-but the cost of losing is too high.

There’s no need to fear every herb. But when your blood is already thin, don’t gamble with the rest.