Cloves: 4 Major Side Effects + Dosage

Reviewed by Sarah Spann, Adv Dip (Nut Med), mATMS
Written by Ravi Teja Tadimalla, Professional Certificate In Food, Nutrition & Health

A few side effects of cloves might make you reconsider consuming them. Cloves are widely used in cooking and for flavoring foods and beverages. Also, it is a key ingredient in soaps, toothpaste, and cosmetics.

Despite the benefits, cloves can also be harmful in certain ways. For example, eugenol, a compound found in cloves, may cause allergies (1).

This article examines the side effects of cloves, their safety, recommended dosage, and any potential drug interactions. Take a look below.

What Are The Side Effects Of Cloves?

1. Can Increase Bleeding

Cloves can increase the risk of bleeding by enhancing the effects of blood-thinning medications, like Warfarin (2).

Cloves also interfere with other antiplatelet medications like aspirin, clopidogrel, dipyridamole, heparin, and ticlopidine. This also increases the risk of bleeding (3).

2. Might Lower Blood Sugar Way Too Much

Cloves help lower blood sugar (4). In a study, clove was found to sustain antihyperglycemic activity for a long time.

This is good news, especially for individuals dealing with diabetes.

But there is a possibility that the spice can lower your blood sugar levels way too much, especially if you are on diabetes medications.

There is no data available to determine if cloves can lower blood sugar levels way too much. But

if you are on diabetes medications, please talk to your doctor before taking cloves.

3. Can Cause Allergies

The eugenol in cloves can cause allergies. The compound reacts directly with body proteins and causes contact dermatitis. It can also cause localized irritation (1).

Cloves may also cause respiratory allergies in a few individuals. This was especially true in the case of workers involved in the spice (clove) processing factories, who inhaled the spice dust. Irritation of the upper and lower respiratory tracts and impaired lung functioning were two of the major symptoms (5).

The eugenol in cloves might also irritate the oral cavity. Individuals consuming too much of it can experience sensations of warmth and pain in the mouth (6).

4. Can Be Toxic

Clove (or the oil) toxicity has been documented in some instances. The oil was found to cause coma, fits, and acute liver damage (7). In the study, a 2-year-old boy administered with 5 and 10 ml of clove oil had slipped into a deep coma in 3 hours.

Though more research is being done on the toxicity of clove oil, there is information on essential oils in general – a group clove oil also belongs to. Essential oils, as a group, may cause fits, coma, renal failure, and even hypoglycemia when used in excess (7).

Cloves have powerful properties. But like any other ingredient, they can cause serious effects if consumed in excess. Hence, it is essential to be aware of the acceptable dosage limits of clove.

How Many Cloves Can You Take In A Day?

According to the World Health Organization, the acceptable daily dosage of cloves per day is 2.5 mg per 1 kg of body weight (8). Anything beyond this can cause complications.

Cloves are known for their numerous benefits. They are used in many cuisines for their unique flavor and aroma. However, they also may increase the risk of bleeding by interacting with certain blood-thinning medications, like warfarin. They also may lower blood sugar way too much. Hence, caution is advised for individuals with diabetes. Cloves may also trigger localized irritation and respiratory allergies and may aggravate oral cavities too. Their oil may be toxic to a few sensitive individuals. If you have any underlying medical condition, consult your doctor before taking cloves.


  1. An unexpected positive hypersensitive reaction to eugenol” BMJ Case Reports, US National Library of Medicine, National Institutes of Health.
  2. Potential interactions between alternative therapies and warfarin.” American Journal of Health-System Pharmacy, US National Library of Medicine, National Institutes of Health.
  3. Clove oil” ScienceDirect.
  4. Effects of Clove and Fermented Ginger on Blood Glucose, Leptin, Insulin and Insulin Receptor Levels in High Fat Diet Induced Type 2 Diabetic Rabbits.” Nigerian Journal of Physiological Sciences, US National Library of Medicine, National Institutes of Health.
  5. Occupational exposure and respiratory health problems among nutmeg production workers in Grenada, the Caribbean” International Journal of Occupational and Environmental Health, US National Library of Medicine, National Institutes of Health.
  6. Eugenol and carvacrol induce temporally desensitizing patterns of oral irritation and enhance innocuous warmth and noxious heat sensation on the tongue” Pain, US National Library of Medicine, National Institutes of Health.
  7. Near fatal ingestion of oil of cloves” Archives of Disease in Childhood, British Medical Journal.
  8. Clove: a precious spice” Asian Pacific Journal of Tropical Biomedicine, US National Library of Medicine, National Institutes of Health.
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Sarah Spann

(Adv Dip (Nut Med), mATMS)
Sarah Spann is a clinical nutritionist specializing in gut health and is based in Brisbane, Australia. She is dedicated to... more