Cloves, the dried flower buds of the Syzygium aromaticum tree, are widely known for their distinctive aroma and flavor. While generally safe when used in small, culinary amounts, concentrated forms—particularly clove essential oil—contain high levels of eugenol, a compound that can pose significant health risks if misused or overconsumed. Understanding what are the serious side effects of clove is crucial for anyone considering its medicinal or supplemental use.
Clove Oil Toxicity and Organ Damage
One of the most dangerous side effects of concentrated clove oil is its potential to cause severe organ damage, particularly to the liver and kidneys. This is especially true in children, who are more susceptible to eugenol toxicity due to their smaller body size.
Acute Liver and Kidney Injury
- Acute Hepatotoxicity: Ingesting large doses of clove oil can lead to severe and rapid liver damage, characterized by elevated liver enzymes and, in extreme cases, acute hepatic necrosis. Cases of severe liver injury have been reported in infants and young children who accidentally ingested clove oil.
- Acute Renal Injury: Along with liver damage, overdose of clove oil can also cause acute kidney injury. Symptoms may include blood in the urine or a decrease in urine output, pointing to serious renal dysfunction.
Symptoms of Overdose Toxicity
- Agitation and central nervous system (CNS) depression
- Seizures or convulsions
- Jaundice (yellowing of the skin or eyes)
- Coma in severe cases
- Respiratory depression or breathing problems
Blood-Thinning Complications
Eugenol, the active component in cloves, has known blood-thinning or antiplatelet properties, which can be hazardous for certain individuals.
Increased Bleeding Risk
- Drug Interactions: Clove supplements can enhance the effects of anticoagulant and antiplatelet medications, such as warfarin, aspirin, and heparin, significantly increasing the risk of bruising and bleeding.
- Bleeding Disorders: Individuals with bleeding disorders, like hemophilia, should avoid clove oil and supplements, as it could exacerbate their condition.
- Pre-Surgery Precautions: Due to its impact on blood clotting, it is recommended to stop taking clove supplements at least two weeks before any scheduled surgery, including dental procedures.
Hypoglycemia (Low Blood Sugar)
Cloves have been shown to lower blood glucose levels, a property that can be beneficial in some contexts but highly dangerous for those with diabetes.
Dangerous Blood Sugar Drops
- Interaction with Diabetes Medication: Combining clove supplements with insulin or other antidiabetic drugs can cause a dangerously low drop in blood sugar (hypoglycemia).
- Vigilance is Key: Individuals managing diabetes should monitor their blood sugar levels carefully and consult a doctor before using cloves medicinally.
Allergic Reactions
While uncommon, some individuals may experience allergic reactions to cloves, either from consumption or topical application.
Symptoms of Allergic Reaction
- Topical Symptoms: Skin irritation, burning, redness, contact dermatitis, or rashes can occur from applying undiluted clove oil.
- Oral Symptoms: In the mouth, excessive or concentrated use can cause irritation of the gums and mucous membranes.
- Systemic Symptoms: More severe, systemic reactions can include hives, swelling, difficulty breathing, or even life-threatening anaphylaxis.
Oral and Respiratory Irritation
Applying concentrated clove oil directly to sensitive areas like the gums can cause significant irritation and tissue damage. Inhaling smoke from clove cigarettes has also been linked to serious respiratory issues.
Oral and Lung Damage
- Tooth and Gum Damage: Prolonged use of undiluted clove oil on the gums can cause inflammation, burning, and harm to tooth pulp and other soft tissues.
- Respiratory Problems: Inhaling clove particles, particularly from smoking clove cigarettes (kretek), can lead to lung infections, bronchitis, and difficulty breathing.
Topical vs. Oral Risks
Comparison of Clove Risks
| Risk Factor | Clove Spice (Culinary Use) | Clove Essential Oil (Medicinal/Topical Use) |
|---|---|---|
| Toxicity | Very low risk; generally safe. | High risk, especially with ingestion or overdose. Can cause severe liver and kidney damage. |
| Blood Thinning | Minimal effect at culinary doses. | Significant risk, especially when combined with anticoagulant medications. |
| Hypoglycemia | Minimal effect at culinary doses. | High risk, can cause dangerously low blood sugar levels in people with diabetes. |
| Allergic Reactions | Low risk, though possible. | Higher risk, especially with direct skin or gum application. Can cause severe irritation. |
| Tissue Irritation | Minimal to none. | High risk, particularly when used undiluted on gums or skin. |
Who Should Be Cautious About Clove Use?
Because of its potent effects, certain individuals should either avoid or use cloves with extreme caution, particularly in concentrated forms. These include:
- Children: Never give clove oil to young children. Small amounts can be toxic and cause liver damage and seizures.
- Pregnant or Breastfeeding Women: Limited safety data means it is best to avoid medicinal amounts of clove during pregnancy and breastfeeding.
- Individuals on Blood Thinners: Anyone taking anticoagulant medication should not use clove supplements due to the increased risk of bleeding.
- People with Diabetes: Clove's blood sugar-lowering effect necessitates careful monitoring for those on diabetes medication to prevent hypoglycemia.
- People with Liver Disease: Given the risk of hepatotoxicity from eugenol, those with pre-existing liver conditions should avoid high doses of clove.
- People with Known Allergies: Individuals with sensitivity to eugenol or other spices should avoid concentrated clove products to prevent allergic reactions.
Conclusion
While a cherished culinary spice, cloves contain a powerful compound, eugenol, that can lead to serious health complications when consumed in concentrated amounts, such as clove essential oil. The most critical risks include organ toxicity affecting the liver and kidneys, potentially life-threatening blood-thinning effects, and dangerous blood sugar drops. It is imperative to distinguish between the safe, small quantities used in cooking and the hazardous concentrations found in essential oils and some supplements. Always consult a healthcare professional before using cloves medicinally, especially if you have underlying health conditions or are on other medications. The potential for severe harm, especially in children and at-risk adults, far outweighs any perceived benefits of improper or excessive use.
How to Use Cloves Safely
To enjoy cloves safely, limit their use to culinary purposes. If considering any medicinal application, particularly with essential oils, follow these steps:
- Dilute, Dilute, Dilute: Always mix clove oil with a carrier oil (like olive or coconut oil) before applying it topically to avoid skin and tissue burns.
- Perform a Patch Test: Before full application, test a small, discreet area of skin to check for allergic reactions or sensitivity.
- Use Small Amounts: If a healthcare provider approves, use only minimal amounts for a short duration. Never ingest clove essential oil.
- Store Safely: Keep clove oil and other concentrated products well out of reach of children and pets, as ingestion can be fatal.
