Can ginger and garlic cause bleeding? Unpacking the risks with herbal supplements

October 14, 2025 •

4 min read

While both ginger and garlic have been used for centuries in traditional medicine and cooking for their health benefits, it is crucial to address a common concern: can ginger and garlic cause bleeding? Research indicates these ingredients contain compounds that possess anti-platelet properties, with the risk being significantly higher with concentrated supplements rather than normal culinary use.

Quick Summary

Though culinary use is generally safe, high-dose ginger and garlic supplements can increase bleeding risk, particularly for those on anticoagulant drugs. Caution is advised, especially before surgery.

Key Points

Supplements Pose the Highest Risk: Concentrated supplements of ginger and garlic carry a significantly higher bleeding risk than culinary use, especially when combined with blood thinners.
Blood Thinner Interaction is Key: People on anticoagulant drugs like warfarin must exercise extreme caution, as ginger and garlic can increase their medication's effect, leading to excessive bleeding.
Surgical Precaution is Vital: Discontinue high-dose ginger and garlic supplements at least two weeks before any scheduled surgery to minimize potential bleeding complications.
Dose Matters: Normal cooking with ginger and garlic is generally safe for most individuals, as the antiplatelet compounds are in lower concentrations.
Consult a Doctor: If you have a bleeding disorder, take medication, or are considering supplements, always consult your healthcare provider to evaluate your individual risk.
Active Compounds are the Cause: The antiplatelet properties of ginger and garlic are attributed to specific compounds, such as gingerols and allicin, which inhibit platelet aggregation.

The Science Behind Ginger's Antiplatelet Effects

Ginger contains active compounds, primarily gingerols and shogaols, which are known to have anti-inflammatory and anti-platelet effects. Platelets are tiny blood cells that help the body form clots to stop bleeding. By inhibiting the action of platelet aggregation, ginger can theoretically reduce the blood's ability to clot effectively.

Culinary Ginger: The amount of active compounds in the ginger used for cooking is typically low. Therefore, consuming ginger in normal food quantities poses little to no risk of significant bleeding for most healthy individuals.
Ginger Supplements: The risk escalates with high-dose, concentrated ginger supplements. Many supplements contain amounts of gingerol and shogaol far exceeding what would be consumed in a typical diet. Some studies, including case reports, have suggested that high-dose ginger can affect clotting factors and increase the risk of bruising and bleeding, especially when taken with other medications.

The Blood-Thinning Power of Garlic

Garlic's antiplatelet effects are primarily attributed to its sulfur-containing compounds, most notably ajoene and allicin. These compounds work by preventing platelets from clumping together, a key step in blood clot formation. Similar to ginger, the concentration of these compounds is a critical factor in determining the bleeding risk.

Raw Garlic: To achieve a noticeable anti-platelet effect from raw garlic, consumption needs to be quite high—more than 5 grams (1-2 cloves) per day, according to some sources. Regular culinary use of cooked or small amounts of raw garlic is considered safe for most people.
Garlic Supplements: Like ginger, concentrated garlic supplements or garlic oil can contain much higher levels of active compounds. Taking these supplements can put individuals at a higher risk of bleeding, particularly when combined with anticoagulant or antiplatelet drugs. A study monitoring patients taking garlic supplements along with aspirin and clopidogrel found that a notable percentage developed thrombocytopenia, a condition involving a low platelet count, and reported symptoms of excessive bleeding.

Interactions with Blood-Thinning Medications

One of the most significant risks associated with ginger and garlic is their potential interaction with blood-thinning medications, also known as anticoagulants or antiplatelet drugs. These medications are prescribed to prevent dangerous blood clots in people with cardiovascular conditions, and their dosage is carefully monitored.

Increased Effects: The antiplatelet properties of ginger and garlic can amplify the effects of these drugs, potentially increasing the risk of uncontrolled bleeding.
Warfarin: Case reports have shown that high-dose ginger supplements can cause a supratherapeutic International Normalized Ratio (INR) in patients on warfarin, indicating a significant increase in bleeding risk. The potential interaction, although not universally confirmed in all studies, warrants extreme caution.
Other Medications: Ginger and garlic can also interact with other drugs that slow blood clotting, including aspirin, clopidogrel, ibuprofen, and naproxen. Combining these with high-dose supplements can lead to increased bruising and bleeding.

Table: Comparing Bleeding Risks of Ginger vs. Garlic


Feature	Ginger	Garlic
Culinary Risk	Generally low risk; safe for most people in normal amounts.	Generally low risk; safe for most people in normal amounts.
Supplement Risk	Increased risk of bleeding with high-dose supplements.	Increased risk of bleeding with high-dose supplements.
Mechanism	Inhibits thromboxane synthetase and affects prostaglandin synthesis.	Inhibits platelet aggregation via compounds like ajoene and allicin.
Drug Interaction	Can increase the anticoagulant effect of warfarin and other antiplatelet drugs.	Can enhance the effects of anticoagulants and antiplatelet drugs.
Surgical Precaution	Stop at least two weeks prior to scheduled surgery.	Limit or stop high intake at least two weeks prior to surgery.

Precautions for Special Cases

While the bleeding risk from moderate culinary consumption of ginger and garlic is minimal for most, certain individuals must be especially cautious:

Those on Blood Thinners: If you are taking anticoagulant or antiplatelet medications, always consult your doctor before starting any herbal supplement. Regular monitoring may be necessary.
Before Surgery: Patients scheduled for surgery should inform their surgeon and anesthesiologist about all medications and supplements they are taking. It is often recommended to stop all herbal supplements, including ginger and garlic extracts, at least two weeks before a procedure to reduce bleeding risks.
Individuals with Bleeding Disorders: People with diagnosed bleeding disorders, such as hemophilia, should consult a doctor before increasing their intake of ginger or garlic, especially in supplement form.
Excessive Intake: Even without medication, consuming extremely high amounts of these herbs over a prolonged period could theoretically affect bleeding time. It is always wise to consume them in moderation.

Conclusion: Can Ginger and Garlic Cause Bleeding?

Yes, ginger and garlic can cause bleeding, but primarily when consumed in high, concentrated doses via supplements, or when interacting with prescription blood-thinning medications. The risk from consuming them in normal culinary amounts is extremely low for most healthy individuals. The antiplatelet compounds, such as gingerols and allicin, are responsible for this effect. Research on the exact extent of these interactions is ongoing, with some studies presenting conflicting evidence, which highlights the importance of individualized medical advice. Before considering any herbal supplement, especially if you are on medication or have an upcoming surgery, it is essential to have a conversation with your healthcare provider to assess your personal risk. You can find more information on specific drug-herb interactions from reliable sources like the NIH.

Frequently Asked Questions

Yes, for most people, consuming ginger and garlic in normal culinary amounts is considered safe. The concentration of active compounds is low and unlikely to cause significant interactions with your medication. The risk is primarily associated with high-dose supplements.

It is highly recommended to stop taking high-dose ginger and garlic supplements at least two weeks before any scheduled surgery. Always inform your surgeon about all supplements you take to assess the bleeding risk.

Yes, high-dose ginger and garlic, especially in supplement form, can interact with warfarin and increase its blood-thinning effects. Case reports have documented increased INR (a measure of clotting time), raising the risk of bleeding.

In ginger, the active antiplatelet compounds are gingerols and shogaols. In garlic, the compounds responsible are allicin and ajoene.

Signs of excessive bleeding can include unusual bruising, prolonged bleeding from cuts, frequent nosebleeds, bleeding gums, blood in urine or stools, or excessive menstrual flow. Report any of these to your doctor immediately.

The risk varies depending on the type and dose of the supplement. Concentrated garlic supplements or garlic oil pose a higher risk than aged garlic extract, which some studies suggest may be safer for patients on warfarin.

High doses are typically defined as those found in supplements, which are far greater than what is normally consumed in food. For ginger, doses over 5 grams a day have been associated with side effects. For raw garlic, consuming more than 1-2 cloves per day consistently could be a concern, but supplements are the most significant risk.