Dong Quai and Warfarin: What You Need to Know About the Bleeding Risk

Nov, 1 2025
Post by : Elara Kingswell

If you're taking warfarin to prevent blood clots, and you're also using Dong Quai for menopause, cramps, or just because it’s "natural," you could be putting yourself at serious risk. This isn’t theoretical. People have ended up in the hospital because of it.

Why This Interaction Is Dangerous

Warfarin is a powerful blood thinner. It works by slowing down your body’s ability to form clots. Too little, and you risk a stroke or pulmonary embolism. Too much, and you could bleed internally-inside your brain, gut, or muscles-with little warning. The goal is to keep your INR (a blood test that measures clotting time) between 2 and 3. Even a small bump above 4.0 increases your risk of major bleeding by more than 300%.

Dong Quai, a root used in traditional Chinese medicine for over 2,000 years, contains natural compounds like ferulic acid and osthole. These substances don’t just mimic warfarin-they work alongside it. They block platelets from sticking together, making your blood even thinner. It’s like turning up the volume on a song you’re already listening to at full blast. You don’t need more warfarin to bleed. Just adding Dong Quai can do it.

Studies show this isn’t rare. One review found that one in five people in Malaysia taking warfarin also used herbal products. In the U.S. and Singapore, 10-20% of anticoagulant users take supplements like Dong Quai without telling their doctor. Many think, "It’s herbal, so it’s safe." That’s the biggest mistake.

How It Works: More Than Just "Additive"

Some sources say the interaction is "pharmacodynamic"-meaning Dong Quai and warfarin hit the same target from different angles. That’s true. But there’s more.

Lab studies show Dong Quai can also interfere with liver enzymes (CYP2C9 and CYP3A4) that break down warfarin. If those enzymes slow down, warfarin sticks around longer. Your body doesn’t clear it as fast. That means even if your dose hasn’t changed, the drug builds up in your system. One study found warfarin’s half-life could stretch from 40 hours to over 80 hours in people taking Dong Quai. That’s more than three days of extra effect.

And it’s not just about the dose. Dong Quai isn’t standardized. One bottle might have 10 mg of active compounds. Another from the same brand, bought six months later, might have 80 mg. The U.S. Pharmacopeia found up to an 8-fold difference in potency between batches. You can’t predict how much you’re really taking. Your doctor can’t adjust your warfarin based on what’s in the capsule.

Real Cases, Real Consequences

A 68-year-old woman in Ohio started taking Dong Quai capsules for hot flashes. Her INR had been steady at 2.6 for months. Two weeks after starting the supplement, she bruised easily, then noticed blood in her urine. Her INR jumped to 5.1. She was hospitalized. No other changes-no new meds, no diet shifts, no alcohol. Just Dong Quai.

Reddit threads from r/anticoagulants in late 2023 had 17 separate posts from people who saw their INR spike after starting Dong Quai. One user wrote: "I thought it was for hormones, not blood. My doctor said if I hadn’t stopped it, I could’ve had a stroke from bleeding inside my skull." HealthUnlocked forums tracked 23 cases between 2020 and 2023 where unexplained INR spikes were traced back to Dong Quai. On average, INR rose by 1.7 points-enough to push someone from safe to dangerous in under a week.

Split scene: woman taking Dong Quai in store vs. same woman bleeding internally in hospital, enzyme shattering between panels.

What the Experts Say

Major medical groups are clear:

The Cleveland Clinic says: "Avoid Dong Quai in warfarin-treated patients due to lack of data." They list it alongside ginkgo and garlic-herbs known to cause bleeding.
The University of California San Diego marks Dong Quai with an upward arrow (↑) under "Increased Risk of Bleeding," alongside fish oil and turmeric.
The American Heart Association calls it a "high-risk herb" for anticoagulant users.
Dr. Catherine Ulbricht, a top pharmacist at Massachusetts General, says: "It can push INR from 2.5 to over 4.0 without warning. That’s not a small risk-it’s a life-threatening one."

Even Memorial Sloan Kettering, which often supports herbal medicine, warns: "Patients using anticoagulants should consult with their physicians before using this herb." They also note Dong Quai may stimulate estrogen-sensitive tumors-another reason cancer patients should avoid it.

What You Should Do

If you’re on warfarin:

Stop taking Dong Quai immediately. Don’t wait for symptoms. Don’t assume "it’s just a little."
Tell your doctor. Even if you’ve been taking it for years. Even if you think it’s harmless. Write it down. Show them the bottle.
Get your INR checked within 3-5 days. Your doctor should monitor you closely for at least two weeks after stopping.
Don’t replace it with another herb. Ginkgo, garlic, ginger, turmeric, and fish oil all carry the same risk. "Natural" doesn’t mean safe with blood thinners.

If you’re not on warfarin but take other blood thinners-like apixaban, rivaroxaban, or dabigatran-Dong Quai may still interact. The research is less clear, but the risk is still there. Better safe than sorry.

Battle in bloodstream: warfarin vs. Dong Quai, ruptured vessels, clock showing INR rise, estrogen patch floating safely above.

Why This Keeps Happening

The FDA doesn’t require herbal supplements to prove safety or effectiveness before selling them. Dong Quai is sold in health food stores, Amazon, and pharmacies with no warning labels. The Dietary Supplement Health and Education Act of 1994 lets companies sell it without oversight.

A 2022 survey found 68% of warfarin users didn’t know herbal supplements could interfere with their medication. But 82% said they’d stop if their doctor told them it was dangerous. That’s the gap. Not ignorance of the herb. Ignorance of the risk.

And the market is growing. Dong Quai sales in the U.S. rose 14.2% annually from 2020 to 2022. People are turning to it for menopause, fatigue, and stress. But few know the cost.

What’s Changing

Good news: Things are shifting.

In January 2025, the European Medicines Agency will require all Dong Quai products sold in EU countries to carry a warning about warfarin interactions. The National Institutes of Health is funding a three-year clinical trial (NCT05523419) to measure exactly how much Dong Quai affects warfarin levels in humans. Results are expected by late 2024.

The American College of Cardiology now lists Dong Quai in the same risk category as St. John’s wort and ginkgo-herbs with proven, dangerous interactions. That’s a big step.

But until then, the safest choice is simple: Don’t take it. If you’re on warfarin, Dong Quai isn’t worth the risk. No matter how natural it seems.

What to Use Instead

If you’re taking Dong Quai for menopause symptoms, talk to your doctor about FDA-approved options like low-dose estrogen patches, SSRIs like paroxetine, or non-hormonal therapies like gabapentin. For menstrual cramps, magnesium, vitamin B1, or heat therapy have solid evidence and no bleeding risk.

There are safe alternatives. You don’t need to risk your life for a supplement with no proven benefit and plenty of proven danger.

Author

Elara Kingswell
I am a pharmaceutical expert with over 20 years of experience in the industry. I am passionate about bringing awareness and education on the importance of medications and supplements in managing diseases. In my spare time, I love to write and share insights about the latest advancements and trends in pharmaceuticals. My goal is to make complex medical information accessible to everyone.
- 1 Nov, 2025

Comments (9)

Marshall Washick
This is one of those posts that makes you realize how little we’re told about what’s really in those "natural" supplements. I’ve seen friends take Dong Quai for years thinking it was harmless-until their INR spiked and they ended up in the ER. It’s not just about warning labels. It’s about the system letting people believe something is safe because it’s old, or herbal, or "traditional." We need better education, not just better warnings.

Thanks for laying this out so clearly. I’m sharing this with my mom who’s on warfarin and just started taking a "women’s health" blend with Dong Quai in it.

She didn’t even know it was in there.
- 1 November 2025
Abha Nakra
As someone who’s studied traditional Chinese medicine for over a decade, I get why people turn to Dong Quai. It’s been used for centuries. But modern pharmacology doesn’t care about tradition-it cares about chemistry. And the chemistry here is terrifying.

The fact that potency varies up to 8-fold between batches? That’s not just risky-it’s criminal. No one should be dosing themselves with something that could kill them because the bottle they bought on Amazon has no quality control.

And yes, the FDA’s hands are tied by that 1994 law. But that doesn’t mean we have to accept it. If you’re on anticoagulants, you’re not just a consumer-you’re a patient. And patients deserve real oversight, not snake oil with a pretty label.

I’ve had patients come in with INRs over 6 because of these supplements. One woman almost bled out from a subdural hematoma after taking a "hormone balance" tea. She didn’t even know Dong Quai was in it.

Stop trusting labels. Start trusting science.
- 1 November 2025
Neal Burton
Of course the medical establishment wants you to believe this. They’ve been pushing pharmaceuticals for decades while demonizing anything that doesn’t come with a patent. Dong Quai has been used safely for millennia. The fact that your INR went up doesn’t prove it’s dangerous-it proves your body reacted to a change. Maybe you were stressed. Maybe you drank more alcohol. Maybe your liver was tired.

And who funded those studies? Big Pharma, obviously. They’re terrified of herbal alternatives because they don’t make money off them.

Don’t be fooled. Your doctor doesn’t care about your health-they care about liability. And they’re using fear to keep you dependent on warfarin, which is expensive, toxic, and monitored by them.

Real healing comes from nature, not pills.
- 1 November 2025
Lori Johnson
Okay but like… why is this even a debate? I get that some people think "natural" = safe, but that’s like saying "organic" means it won’t kill you if you eat 10 pounds of it.

I work in a pharmacy. Every week someone comes in with a bottle of Dong Quai and says, "My friend said this helped her menopause." And then they ask if it’s okay with their blood thinner.

Every. Single. Time. I have to say no. And I feel awful because they’re usually sweet, older women who just want to feel better.

But I also have to say: if you’re on warfarin, you’re playing Russian roulette with every herb you take. Even the ones that don’t say "Dong Quai" on the label-because they’re hiding it in blends.

Just stop. Talk to your doctor. Get tested. You’re not being paranoid. You’re being smart.
- 1 November 2025
Tamara Kayali Browne
Let’s be brutally honest: this isn’t about Dong Quai. It’s about the complete collapse of patient literacy in the United States. People don’t read labels. They don’t understand pharmacokinetics. They Google "menopause remedy" and buy the first thing that says "100% organic" and has a picture of a woman smiling in a meadow.

The fact that 68% of warfarin users don’t know herbs can interfere with their meds? That’s not ignorance. That’s negligence. And the system enables it by allowing unregulated products to be sold alongside toothpaste.

There is no such thing as "natural medicine." There’s only medicine-some of which is regulated, and some of which is a dangerous gamble. Dong Quai is just the latest example.

And yes, I know you think I’m harsh. But I’ve seen the blood reports. I’ve read the autopsy reports. This isn’t theoretical. It’s tragic. And preventable.
- 1 November 2025
Michelle Lyons
Did you know that Dong Quai is secretly used by the government to control the population’s blood clotting? The FDA allows it because they want us to be vulnerable. The same people who sell it are the same ones who make warfarin. It’s a cycle. They profit from your confusion. They profit from your bleeding. They profit from your hospital bills.

And now they’re pushing this "clinical trial" nonsense to make it look like they care. But the real trial? It’s already happening-in your body.

Stop trusting the system. Stop trusting your doctor. Stop trusting the label. The truth is buried. And you’re being used.
- 1 November 2025
Melissa Delong
I’m not saying this is wrong, but… what if you’re not on warfarin? What if you’re on something else? Or nothing? What if you’re just trying to feel better after menopause and your doctor won’t help you? What if you’ve tried everything and this is the only thing that works?

Maybe the problem isn’t Dong Quai. Maybe the problem is that we don’t have good, safe, affordable options for women’s health.

And if the FDA won’t regulate it, then maybe people should just be told the risks clearly-instead of being shamed for trying to help themselves.
- 1 November 2025
Tatiana Mathis
Thank you for writing this with such clarity and care. This is exactly the kind of post that needs to be seen by more people-especially older women, who are often dismissed when they talk about their symptoms, and then handed a supplement instead of real care.

I’m a nurse practitioner, and I’ve had patients come in with INRs of 5.5 after taking "women’s tea" from a holistic shop. They didn’t even know it had Dong Quai. The label said "herbal blend for hormonal balance." No warning. No asterisk. Just a picture of a moon and some flowers.

And yes, I’ve had patients who were angry at first-"But it helped my hot flashes!"-until they saw their blood work and understood what could’ve happened.

There’s a real gap here between what people want and what’s actually available. We need better access to FDA-approved alternatives, not just more warnings. But until then, this post is a lifeline.

Please keep sharing this. And if you’re reading this and you’re on warfarin? Please, please stop. And talk to your provider. You’re not being dramatic. You’re being alive.
- 1 November 2025
Nishigandha Kanurkar
STOP. RIGHT. NOW. DON’T. TOUCH. DONG. QUAI. EVER. IF. YOU. ARE. ON. WARFARIN. OR. ANY. BLOOD. THINNER. OR. EVEN. IF. YOU. THINK. YOU. MIGHT. BE. AT. RISK. THIS. IS. NOT. A. DRILL. PEOPLE. ARE. DYING. FROM. THIS. AND. NO. ONE. IS. TELLING. YOU. BECAUSE. THE. INDUSTRY. MAKES. MONEY. OFF. YOUR. DEATH. AND. YOUR. HOSPITAL. BILLS. AND. YOUR. TRAUMA. I. SAID. STOP. NOW. I. MEAN. IT.
- 1 November 2025