ConditionBlood & immune system
Herbal Supplement Bleeding: Which Supplements Raise Bleeding Risk
Herbal supplement bleeding is abnormal bruising or bleeding caused or made worse by herbs and dietary supplements that thin the blood, such as ginkgo, garlic, high-dose fish oil, vitamin E, turmeric and dong quai. On their own these rarely cause serious bleeding in healthy people. The risk rises sharply when they are combined with blood thinners, aspirin or NSAIDs, before surgery, or in people with a bleeding disorder. Telling your doctor and pharmacist about every supplement is the main protection.
Also called: Supplement-induced bleeding, herb-related bleeding, dietary supplement bleeding risk, herb-drug interaction bleeding
At a glance
- What it is
- Bleeding or bruising made more likely by supplements that affect platelets or clotting.
- Main culprits
- Ginkgo, garlic, ginger, ginseng, fish oil, vitamin E, turmeric, dong quai, danshen, feverfew, willow bark.
- Highest risk
- With warfarin, other anticoagulants, aspirin, clopidogrel or NSAIDs; before surgery; in bleeding disorders.
- Warning signs
- Easy bruising, nosebleeds, bleeding gums, heavy periods, blood in urine or stool.
- What to do
- Tell your care team about every supplement; most should be stopped about 1 to 2 weeks before surgery.
When to get help
Call 911 or go to the ER
- Vomiting blood or material like coffee grounds, black tarry stools, or large amounts of blood from the rectum
- Sudden severe headache, confusion, weakness or trouble speaking while taking a blood thinner
- Bleeding that will not stop after 10 to 15 minutes of firm pressure
- Heavy bleeding after a fall or head injury while on a blood thinner
See a doctor within a day or two
- Pink, red or brown urine
- Nosebleeds that keep coming back or last more than 20 minutes
- Large unexplained bruises, or many small red or purple spots on the skin
- An INR result that is suddenly high after starting a new supplement
Book a routine appointment
- Planning surgery, a dental extraction or a procedure while taking supplements
- Bleeding gums when brushing, or heavier periods since starting a supplement
- Wanting to start a new supplement while taking any prescription medicine
How supplements increase bleeding
Supplements raise bleeding risk in three main ways:
- Reducing platelet stickiness: platelets are the cells that plug a damaged blood vessel. Ginkgo, garlic, ginger, fish oil, turmeric and feverfew all reduce platelet clumping in laboratory studies.
- Containing natural anticoagulants: dong quai and some other plants contain coumarin compounds related to warfarin, and willow bark and meadowsweet contain salicylates related to aspirin.
- Changing how medicines are broken down: some herbs alter liver enzymes and so raise or lower blood levels of warfarin and other drugs.
The effect of any one supplement is usually small. Problems arise when effects stack up, for example ginkgo plus fish oil plus aspirin plus a blood thinner.
Supplements linked to bleeding
| Supplement | How it may affect bleeding | Notes |
|---|---|---|
| Ginkgo biloba | Reduces platelet function | Case reports of brain and eye bleeding, mostly in people also on blood thinners |
| Garlic (concentrated supplements) | Reduces platelet function | Normal amounts in food are fine |
| Ginger (high doses) | Mild antiplatelet effect | Food amounts are fine |
| Fish oil (omega-3) | Mild antiplatelet effect at high doses | Usually safe at ordinary doses; extra caution above about 3 g per day of EPA plus DHA |
| Vitamin E (high doses) | Interferes with platelets and vitamin K | Higher bleeding risk seen with high-dose supplements |
| Turmeric or curcumin | Antiplatelet effect; may raise warfarin effect | Concentrated extracts more than culinary use |
| Dong quai | Contains coumarins; raises INR with warfarin | Avoid with blood thinners |
| Danshen | Raises warfarin effect | Avoid with blood thinners |
| Feverfew | Inhibits platelets | Used for migraine |
| Willow bark, meadowsweet | Contain salicylates like aspirin | Avoid with aspirin or NSAIDs, and in children and teens |
| Saw palmetto | Case reports of surgical bleeding | Evidence weak |
| Glucosamine (with or without chondroitin) | Case reports of higher INR with warfarin | Monitor INR if starting |
Some supplements do the opposite and reduce warfarin's effect, raising clot risk: St John's wort, high-vitamin K products such as green tea extracts and alfalfa, and ginseng (especially American ginseng). Starting or stopping these can still destabilize anticoagulation.
Who is at highest risk
- people taking warfarin, apixaban, rivaroxaban, dabigatran, edoxaban or heparin
- people on antiplatelet drugs such as aspirin, clopidogrel, prasugrel or ticagrelor
- regular users of NSAIDs such as ibuprofen and naproxen
- anyone with a bleeding disorder, low platelets or liver disease
- people having surgery, dental extractions, epidurals or injections
- older adults taking several medicines and supplements
Warning signs
- bruising easily or bruises you cannot explain
- frequent or prolonged nosebleeds
- bleeding gums when brushing or flossing
- heavier or longer periods
- cuts that keep oozing
- blood in the urine or black, tarry stools
- small red or purple dots on the skin (petechiae)
How doctors assess it
A doctor or pharmacist will ask about everything you take, including vitamins, teas, powders, tinctures and products bought online. Bring the actual bottles if you can, since products labeled the same can contain very different amounts.
Tests may include:
- complete blood count, including platelets
- INR and other clotting times, especially if you take warfarin
- sometimes platelet function tests or tests for von Willebrand disease, if bleeding continues after supplements are stopped
Treatment
- Stop the supplement. Most antiplatelet effects wear off within 1 to 2 weeks, as new platelets are made.
- Manage active bleeding with firm pressure for nosebleeds and cuts. Serious bleeding needs emergency care.
- Correct anticoagulant levels: if warfarin's INR is too high, your clinic may hold doses or give vitamin K. Do not change blood thinner doses yourself. See anticoagulant complications.
- Look for a source: heavy bleeding, such as from the stomach, may reveal an ulcer or another problem that needs treatment in its own right.
Supplements and surgery
Many surgeons and the American Society of Anesthesiologists advise stopping herbal supplements about 2 weeks before planned surgery. Fish oil, vitamin E, ginkgo, garlic, ginseng, turmeric and others with blood-thinning effects are the main concern. Follow your surgical team's specific instructions, and do not stop prescribed aspirin or blood thinners unless they tell you to.
Safer supplement use
- Keep an up-to-date list of all supplements with your medicine list.
- Ask a pharmacist before starting a new supplement, especially with a blood thinner.
- If you take warfarin, have your INR checked within about a week of starting or stopping any supplement.
- Choose products with third-party testing seals (such as USP or NSF), since quality and dose vary widely.
- Remember that "natural" does not mean safe with medicines.
Frequently asked questions
Which supplements thin your blood?
The best-known are ginkgo biloba, garlic and ginger supplements, high-dose fish oil, high-dose vitamin E, turmeric or curcumin, dong quai, danshen, feverfew and willow bark. Their effects are generally mild alone but can add to blood thinners, aspirin and NSAIDs, raising the risk of bleeding.
Is it safe to take fish oil with blood thinners?
At ordinary doses, fish oil usually adds little bleeding risk, and many people on blood thinners take it. At higher doses the effect increases. Ask your doctor or pharmacist before combining them, report any unusual bruising or bleeding, and mention it before surgery.
Can turmeric cause bleeding?
Turmeric in food is safe. Concentrated turmeric or curcumin supplements can reduce platelet function and may increase the effect of warfarin, so bleeding risk rises when they are taken with blood thinners or antiplatelet drugs. Check with your doctor before using them if you take these medicines.
Which supplements should I stop before surgery?
Most surgical teams ask you to stop herbal and dietary supplements about 2 weeks before surgery, particularly ginkgo, garlic, ginseng, ginger, fish oil, vitamin E, turmeric, dong quai and St John's wort. Always follow the specific instructions you are given, and never stop prescribed medicines without asking.
How long after stopping ginkgo does bleeding risk go back to normal?
Platelets live about 7 to 10 days, so the antiplatelet effect of ginkgo and similar supplements generally fades within about 1 to 2 weeks of stopping. That is why a 2-week break is commonly advised before planned surgery or procedures.
Sources
This guide was written from current patient and clinical guidance, including:
- NIH National Center for Complementary and Integrative Health: Herb-drug interactions
- NIH Office of Dietary Supplements: Omega-3 fatty acids and Vitamin E fact sheets
- MedlinePlus: Herbs and supplements
- American Society of Anesthesiologists: Herbal and dietary supplements and anesthesia
- US Food and Drug Administration: Mixing medications and dietary supplements can endanger your health