What Are Cloves?

How to use clove spices, oil, and traditional medicine

Clove is a spice that is rich in antioxidants, vitamins, and minerals. Cloves have been used in traditional Chinese medicine and Ayurvedic medicine to strengthen the immune system, reduce inflammation, and aid in digestion.

Cloves are sourced from an evergreen tree (Syzygium aromaticum) native to Indonesia. Although now, it is grown in other parts of the world, such as South America. The spice is used in savory dishes, desserts, and drinks. It is also added to mouthwashes, creams, gels, and oils.

This article explores the research to support the use of cloves and clove oil for different medical uses. It also discusses potential side effects and warnings associated with cloves.

Close-Up Of Cloves In Spoon On Table
 

Dietary supplements are not regulated like drugs in the United States, meaning the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before products are marketed. When possible, choose a supplement tested by a trusted third party, such as USP, ConsumerLabs, or NSF.

However, even if supplements are third-party tested, that doesn't mean they are necessarily safe for all or effective in general. Therefore, it is important to talk to your healthcare provider about any supplements you plan to take and check in about potential interactions with other supplements or medications.

Supplement Facts

  • Active ingredient(s): Eugenol
  • Alternate name(s): Clove, clove extract, clove oil
  • Suggested dose: Insufficient data
  • Safety considerations: Not enough reliable data to know if it is safe to use in large amounts while pregnant or breastfeeding; clove oil is not safe for children

Purported Uses of Cloves

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.

Cloves are most commonly recognized as a spice used in cooking, but they have also been used for centuries to treat various health concerns. Cloves are thought to have some anti-inflammatory properties and have been promoted to help with toothache, dental pain, plaque buildup, hangovers, indigestion, and more. However, there is very little evidence to support taking more cloves than what someone would normally consume with their food.

Preliminary research has examined cloves' use in easing dental pain or toothaches and lowering blood sugar levels. Some laboratory research has also looked at its effects on cancer cells, though these studies were not done in humans.

Dental Pain

Clove oil is perhaps best known as a remedy for toothache and dental pain. In one study of 73 adults, for instance, researchers found that clove-based gel was comparable to benzocaine (a local anesthetic) in its ability to ease pain resulting from injections in the mouth.

Other research has indicated that the clove's antibacterial properties may help reduce oral bacteria that can lead to the development of plague, gingivitis, and cavities.

Blood Sugar Effects

Some preliminary evidence suggests that eugenol may have a lowering effect on blood sugar levels. However, most of the research has been in animal models, so it is too early to recommend specific doses to help manage blood sugar in humans.

One human study on healthy volunteers found that 12 days of clove extract use significantly lowered blood sugar levels more than placebo. But the difference in change was only 3 milligrams per deciliter, which is of questionable clinical significance. Further well-designed research is needed.

Cancer

While some laboratory studies have looked at the effect of cloves on cancer cells, this research was not done in humans and is not solid evidence of cloves' role in treating or preventing cancer.

One review on eugenol suggests that it may be an effective cancer therapy alone or combined with chemotherapy.

However, it is important to know that supplements and herbal remedies can not treat, cure, or prevent disease. Forgoing traditional chemotherapeutics and relying on alternative therapies can worsen outcomes. Talk to your cancer care team before starting any new supplement or herbal product.

What Are the Side Effects of Cloves?

Low doses of clove oil appear to cause few side effects but can result in local irritation, rare allergic reactions, and contact dermatitis. However, consuming large doses can cause severe side effects, such as liver and kidney damage, seizures, and coma.

Caution for Children

Clove oils can be toxic to children. Store products that contain clove oil away and out of reach of children in your household.

Precautions

There is insufficient safety data on cloves or clove oil in pregnant and breastfeeding people. Therefore, it is recommended to avoid supplementing with it.

Clove oil should not be used for children. Even small amounts of clove oil have been reported to cause severe side effects such as seizures and liver damage.

One case report detailed a child who ingested clove oil and experienced disseminated intravascular coagulation (DIC), a rare but serious blood clotting condition, and hepatocellular necrosis (death of hepatocytes, which are liver cells).

Other precautions to keep in mind include the following:

  • Avoid taking clove oil if you have a bleeding disorder.
  • Stop using cloves at least two weeks before planned surgery, as it could lead to increased bleeding.
  • Cloves also come in cigarette form for inhalation. Smoking clove cigarettes is likely unsafe and can lead to poor health.

Dosage: How Much Should I Take?

There isn't enough data to suggest an appropriate dose of cloves. Talk to your healthcare provider or a registered dietitian and nutritionist about specific types of clove products and how to use them.

What Happens If I Take Too Much?

There is a limited amount of information on the effects of clove toxicity. However, ingesting high amounts may lead to severe side effects, such as:

  • Liver or kidney damage
  • Acute onset of seizures
  • Coma

In a case report, one child who consumed clove oil experienced seizures and liver damage. If you have clove oil, keep it stored away and out of reach of children and pets to prevent accidental consumption.

Interactions

Before using any supplement product, talk to your healthcare provider or pharmacist about potential drug or food interactions. Share any prescription or over-the-counter (OTC) medications, vitamins, or herbal supplements you are currently taking.

Cloves may have a lowering effect on blood sugars. Adding them to a regimen that already includes diabetes medications could increase the risk of developing hypoglycemia.

Adding cloves when already on blood thinners or anticoagulants could lead to a greater risk of bruising and bleeding.

How to Store Cloves

Follow the directions on the product labels for proper storage. Always store out of reach of children and pets to prevent an accidental overdose.

Frequently Asked Questions

  • Does clove oil affect blood sugar?

    A small study found clove extract may help to reduce post-meal blood sugar spikes. However, the research was performed on healthy volunteers and not people with diabetes. More studies are needed to validate these effects. Until then, there is not enough evidence to recommend using clove oil as a means to lower blood sugar.

  • Are clove cigarettes or cigars safe?

    No. Clove cigarettes, also known as kreteks, often contain more tar and nicotine than conventional cigarettes. The FDA banned the sales of flavored cigarettes in the United States, including clove cigarettes, after enforcing the Family Smoking Prevention and Tobacco Control Act.

Sources of Cloves & What To Look For

Clove oil is available at most health food stores and supermarkets.

According to the review on cloves in the Commission E Monographs, detailing the German authority's approved preparations of clove oil, 1% to 5% essential oil solutions are recommended for mouthwashes and undiluted oil is recommended for official dental use.

As with any supplements, look for one with a USP, ConsumberLabs, or NSF label. This indicates that the product has been third-party tested and it contains the amount of ingredients listed on the supplement bottle.

Summary

Cloves are a spice commonly used in cooking, but they can also be available in gels, creams, and mouthwashes.

Cloves have been used in traditional Chinese medicine and Ayurvedic medicine. They've been studied for uses in lowering blood sugar and dental pain or toothache relief. However, there is little evidence of the benefits of taking cloves in amounts greater than what you would get from your regular diet.

Be sure to discuss any supplements you plan to take with your healthcare provider.

13 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Jennifer Lefton, MS, RD/N, CNSC, FAND
Jennifer Lefton, MS, RD/N-AP, CNSC, FAND is a Registered Dietitian/Nutritionist and writer with over 20 years of experience in clinical nutrition. Her experience ranges from counseling cardiac rehabilitation clients to managing the nutrition needs of complex surgical patients.

Originally written by Cathy Wong
Cathy Wong

Cathy Wong is a nutritionist and wellness expert. Her work is regularly featured in media such as First For Women, Woman's World, and Natural Health.

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