People who should avoid eating cloves (and why)

Cloves (scientific name Syzygium aromaticum), the tiny, dried flower buds of the Syzygium aromaticum tree, are one of the most sought-after spices in the whole world. Across the world, they are widely used as an aromatic spice and in traditional medicine. They are fragrant, potent as spice, and used globally in cooking and even in aromatherapy. Their warm aroma and sweet-spicy flavor make them popular in curries, masalas, baked goods, teas, and remedies.

But cloves’ appeal goes beyond just as a taste, flavour, and scent enhancer. Apart from adding a rich and aromatic touch to foods, they carry powerful compounds like eugenol that are often praised for their health benefits. Yet, while cloves in moderate amounts are generally safe for most people, certain groups or conditions may face risks when using cloves, especially in concentrated forms such as oils, extracts, or supplements.

While small amounts in food are generally safe, certain individuals may face serious side effects or harmful interactions if they consume clove oil, clove supplements, or large doses of clove extract. Here, in this guide, we’ll highlight who should avoid eating or using cloves, what health risks may arise, the scientific evidence behind these warnings, and practical guidance for safer use. Whether you enjoy a few cloves in cooking or consider using clove oil or supplements, it’s vital to know the possible downsides.

Clove oil can be extremely dangerous for young children. Even small oral doses have been linked to seizures, liver damage, and life-threatening fluid imbalances in reported cases. The delicate balance of organs and metabolism in early life makes children far more susceptible to the toxicity of eugenol, the primary active compound in cloves. Therefore, clove oil or supplements should not be given to children (especially under 2 years) unless under strict medical supervision. Even in older kids, any use should be conservative and carefully monitored.

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Eugenol in cloves, when taken in high doses, has direct cytotoxic effects on liver cells. There are documented cases of acute liver injury after ingestion of concentrated clove oil, resulting in jaundice, elevated liver enzymes, and sometimes hepatic necrosis. If you already have liver disease (like hepatitis, fatty liver, cirrhosis), your liver’s reserve capacity is compromised, and adding another hepatotoxic exposure is risky. Thus, high-dose clove use should be avoided or strictly supervised by a physician.

Cloves (particularly clove oil or extracts) contain eugenol, which appears to slow blood clotting. This action, combined with medications that reduce clotting (such as warfarin, aspirin, clopidogrel, certain NSAIDs), may amplify bleeding risk, leading to bruising, nosebleeds, gastrointestinal bleeding, or worse. Medical guidelines advise stopping clove use at least two weeks before any surgery or dental procedure to reduce intraoperative bleeding risk.

Some studies suggest cloves may lower blood sugar, possibly via effects on glucose metabolism in the liver or through enhancing insulin sensitivity. While that may sound beneficial, in individuals already on diabetes medications, the combined effect may lead to hypoglycemia (blood sugar falling too low). People using insulin or other glucose-lowering drugs should be cautious and monitor their blood sugar closely if they introduce cloves in medicinal amounts.

Culinary amounts of cloves (i.e., as a spice in food) are generally considered safe in pregnancy. However, medicinal or supplemental doses lack sufficient safety data. Because eugenol and other compounds can cross into the bloodstream, there is concern about effects on fetal development or on the baby through breast milk. For safety, it's recommended to avoid clove oil and supplements during pregnancy and breastfeeding unless prescribed by a specialist.

Topical application of clove oil or gels (especially in the mouth) can lead to irritation, burning, ulceration, or mucosal damage. Some individuals may have allergic reactions to clove or its compounds, manifesting as dermatitis, rashes, or swelling. If you have known spice sensitivities, peptic ulcers, or oral conditions (e.g., exposed gums, sores), you should avoid applying concentrated clove products to those tissues.

In large, concentrated amounts, cloves may irritate the digestive tract and cause nausea, vomiting, diarrhea, or stomach upset. If you have ulcers, gastritis, acid reflux, or irritable bowel syndrome, high doses of cloves or oils may worsen symptoms.

Clove (or eugenol) may modulate liver enzyme systems (e.g., CYP1A2, CYP2C9, CYP2D6, CYP3A4), which are responsible for metabolizing many drugs. This may alter the drugs’ levels – either potentiating side effects or reducing effectiveness. If you are on medications that are processed by these enzyme systems, adding high doses of clove.

This article is for informational purposes only and is not a substitute for professional medical advice. While cloves may offer health benefits, individual results may vary. Consult a qualified healthcare professional before using cloves for medicinal purposes, especially if you have existing health conditions or are taking medication.