Do Cloves Have Bad Effects? Understanding the Risks and Safe Use

December 19, 2025 •

2 min read

While cloves are celebrated for their antioxidant and anti-inflammatory properties, excessive consumption, particularly of concentrated clove oil, can lead to serious adverse effects. The key lies in understanding the difference between culinary use and therapeutic doses, and how certain populations may be at higher risk.

Quick Summary

This article explains the potential negative effects of cloves, detailing risks associated with high doses, concentrated oils, and specific medical conditions like bleeding disorders or diabetes. It outlines why moderation is crucial and provides guidance on safe usage.

Key Points

High Eugenol Content: The compound eugenol is responsible for both cloves' benefits and risks, especially in high concentrations found in clove oil.
Blood-Thinning Effect: Cloves can slow blood clotting and should be avoided by individuals with bleeding disorders or those on blood-thinning medication.
Liver Toxicity Risk: High doses of concentrated clove oil can cause severe liver damage and should be kept away from children.
Drug Interactions: Cloves can interfere with various medications, including blood thinners and diabetes drugs, by altering blood clotting and sugar levels.
Oral and Digestive Irritation: Undiluted clove oil can cause burns and irritation to oral tissues, while excessive spice can lead to gastrointestinal upset.
Consult a Professional: Medical advice is crucial before using clove supplements or oils, particularly for those with underlying health conditions, pregnancy, or in children.

Clove's Powerful Compound: The Role of Eugenol

Eugenol is the main active component in cloves, making up 70-90% of clove essential oil. It contributes to clove's benefits but also its risks, especially at high concentrations found in undiluted oil or large supplements.

Potential Side Effects of Overconsumption

Consuming excessive amounts of cloves can lead to several adverse effects:

Digestive Issues: High quantities can irritate the stomach, potentially causing nausea, vomiting, heartburn, and diarrhea.
Blood-Thinning: Eugenol can slow blood clotting, increasing the risk of bruising and bleeding. Individuals with bleeding disorders or those taking anticoagulant medications should be cautious. It is recommended to stop clove use two weeks before surgery.
Blood Sugar Levels: Cloves might lower blood sugar. Diabetics, particularly those on medication, should monitor their levels to avoid hypoglycemia.

Specific Risks Associated with Clove Oil

Clove oil, due to its high concentration of eugenol, poses greater risks than whole cloves. Ingestion can be particularly dangerous:

Organ Damage: As little as 5-10 mL of clove oil can be toxic, potentially causing severe liver and kidney damage, especially in children. Signs can include jaundice and tissue damage.
Neurological Effects: Overdosing on clove oil has been linked to seizures and coma.
Oral Irritation: Applying undiluted clove oil directly to oral tissues can cause burning, irritation, and damage. While used for toothaches, misuse can worsen the problem.

A Comparison of Clove Forms


Feature	Whole Cloves (Culinary Use)	Clove Supplements/Extracts	Clove Essential Oil (Undiluted)
Eugenol Concentration	Low	Moderate to High	Very high (70-90%)
Safety Profile	Generally safe in moderation.	Use cautiously, dosage varies.	High risk, toxic if ingested.
Primary Risks	Mild digestive upset.	Drug interactions, bleeding risk.	Liver damage, seizures, oral burns, skin irritation.
Recommended Use	Food flavoring, chew small amounts.	Consult healthcare provider, follow instructions.	External, diluted use only; never swallow.

Interactions with Medications and Conditions

Cloves can interact with various drugs and may be contraindicated for certain health issues.

Blood Thinners: Can enhance the effects of anticoagulants like warfarin or aspirin, increasing bleeding risk.
Diabetes Medication: May lower blood sugar, interfering with insulin and other diabetes drugs.
Liver Metabolism: Cloves can affect how the liver processes certain medications.

For more detailed information on eugenol, consult the National Institutes of Health.

Conclusion: Moderation is Key

While whole cloves are safe and beneficial in culinary amounts, concentrated forms like clove oil and high-dose supplements carry significant risks. Eugenol can cause liver damage, increase bleeding risk, and dangerously lower blood sugar if used improperly or excessively. Always consult a healthcare professional before using cloves for medicinal purposes, especially if you have existing health conditions or take medication. Using cloves moderately in food is generally considered safe and adds flavor.

Frequently Asked Questions

Yes, eating too many whole cloves can cause digestive issues such as stomach irritation, nausea, and diarrhea. While generally safe in small culinary amounts, moderation is important to avoid these effects.

Yes, ingesting concentrated clove oil is toxic and can cause severe liver damage, particularly in children. It should never be swallowed and is meant for topical use only in a diluted form.

Individuals with bleeding disorders, those on blood-thinning medication, people with diabetes, and young children should avoid concentrated clove products. Pregnant and breastfeeding women should also exercise caution and consult a doctor.

Yes, cloves can interact with medications for diabetes (lowering blood sugar) and anticoagulants (increasing bleeding risk). They may also affect drugs metabolized by certain liver enzymes.

While clove oil is a traditional remedy for toothaches, it should be used with caution and always diluted. Applying undiluted oil directly to the gums can cause burning and tissue damage.

Yes, some people can be allergic to cloves or the eugenol they contain. Allergic reactions can include skin rashes, irritation, or respiratory issues, especially in sensitive individuals.

There is no definitive daily intake for clove supplements, but culinary amounts are considered safe. For potent clove oil, the World Health Organization suggests a daily intake of no more than 2.5 mg per kilogram of body weight.