It may be the most popular essential oil of all time. Even at places with a poor selection, like Whole Foods and Sprouts in the US, or Boots and Llloyds Pharmacy in the UK, you are bound to find this type on the shelf.

99% of people are buying because they like what clove oil smells like; sweet as vanilla and spicy as pepper, both at the same time! Some say it’s the scent of a freshly baked pumpkin pie out of the oven. The main active component responsible for the smell – eugenol (acetyleugenol) – is so strong that just a couple drops in a diffuser will engulf a small room with this sweet peppery aroma.

It has the best scent according to many, and the best antioxidant content according to science.

fresh green cloves growing on tree

What the fresh buds look like before drying. Photo by Prof. Chen Hualin [CC BY-SA 4.0], via Wikipedia

Cloves are the dried flower buds of a tree that’s native to Indonesia. These aromatic buds are neck and neck for being the highest antioxidant spice in the world.

Their ORAC value is 290,283. Only sumac is more at 312,400.

It’s no surprise then that the highest antioxidant essential oil is cloves, hands down. Its ORAC value is a jaw-dropping one million!

To be precise, it’s 1,078,700. On an ounce to ounce comparison, that’s over 300x more antioxidants than goji berries!

If you compare it to the antioxidants in essential oils broadly, you will see the 2nd place – myrrh – is 65% lower. Some of the most popular are not even that high. Peppermint oil is 37,300 (94% lower), Cassia cinnamon is 15,170 (98.6% lower) and lavender is 360 (99.99% lower).

Considering this potential health benefit of clove, it may seem like a no-brainer for anyone who uses essential oils. Not so fast though, because there are dangers you need to know.

Clove oil side effects

Most products use the Syzygium aromaticum species and derive the oil from the plant’s bud, which contains up to 87% eugenol. Less commonly, some brands use clove leaf oil or a blend of it. When derived entirely from the leaf, it’s 77% eugenol. Stem oil, another source, is up to 87% eugenol. So whichever form you fancy, it’s going to have a lot. This active component of clove oil is responsible for its medicinal uses and therapeutic benefits, but also most of the adverse reactions. (1) (2) (3)

health warning on clove oil bottleBecause it’s active ingredient is eugenol, the side effects of clove essential oil are the same and they can include:

  • Skin irritation
  • Headache
  • Shallow and/or rapid breathing
  • Burning sensation in mouth and throat when used orally
  • Damage to gums and dental tissue
  • Increased bleeding due to less blood clotting
  • Interactions with anticoagulants/antiplatelet drugs
  • Abdominal pain
  • Diarrhea
  • Vomiting
  • Seizures
  • Liver damage, especially in children
  • Bodily fluid imbalances
  • Coma
  • Death
  • Unknown pregnancy and breastfeeding safety

That’s according to data reported by the U.S. National Library of Medicine. (4) (5)

While it’s not a government document, if you look at a clove oil MSDS (Material Safety Data Sheet) from a given supplier, you will see similar dangers noted. (6)

To be clear, most of those side effects would require drinking or eating clove oil. Topical applications of the skin and gums can cause irritation, headache, and other reactions, but are unlikely to cause the serious side effects associated with an overdose by ingestion. However it does not take much eugenol to cause toxicity when ingested, which is why people who use it for dry socket, gum pain, and toothache are potentially playing with fire.

Is clove oil safe?

whole clove spiceIt has been used for medicinal purposes in dentistry, but that is with carefully controlled amounts under the supervision of a professional. While those applications are considered safe, they can be dangerous in the form of a do-it-yourself home remedy.

As part of aromatherapy and use in skin cream and massage gels, an allergic reaction to clove oil is rare but can occur. Itchiness and hives are the most common reaction. In high dosages, the scent will cause headaches for many people. To use it safely, you need to follow the manufacturer’s instructions and discontinue use if you experience any of these adverse effects.

Can you use clove oil when pregnant?

Given its propensity to cause increased bleeding, pregnant women and those who are breastfeeding would be wise to avoid it. Uses of the spice in food is  still considered “likely safe” according to the National Library of Medicine data sheet, but foods are a much less concentrated form of eugenol. To avoid the potential health risks for both baby and mother, during pregnancy avoid the essential oil and food sources.

For everyone else, the good news is that a little goes a long ways. If used in skin care products, given its high antioxidant potential, a few drops mixed with a face cream should be plenty sufficient for that potential benefit, as well as the pleasant scent.
One of the myths you will hear is that clove oil kills nerves. That’s not how its numbing mechanism works.

Before a lidocaine or Novocain injection, dentists use to swab your gums with it for 5 minutes for some preliminary anesthetic action (today they use more effective chemicals). The eugenol works like other local anesthetics, by temporarily blocking the nerve that carries the pain signal to your brain. There is no “killing” of the nerve involved, as some people believe.

If an EO is highly concentrated and burns your skin – not just figuratively but literally – then yes, that could cause tissue damage which might include your nerves. However that extreme is unrelated to the anesthetic medical uses of clove and eugenol in dentistry.

What is clove oil used for?

Dental medical uses of it have a long history with clinical research. But aside from that use, you have blogs claiming it can help with Candida yeast, ear infections, urinary tract infections, herpes, acne, and an aid to quit smoking. Which of these purported benefits are based on science and which are totally bogus?

What follows is a list of 10 frequently purported uses and what research – if any – there is to support them. Beginning with the least controversial one…

1. Toothache

dentist evaluating female patientIts history in dentistry is long, but not as a go-to treatment for toothaches.

It’s used in temporary cement. While a permanent crown is being fabricated, a patient often will wear a temporary. This may be affixed with a zinc oxide and clove oil filling. Though more often it’s pure eugenol which is used. The amount in the adhesive will only be a low single-digit percentage, to aid with the nerve pain of the exposed tooth underneath. It’s no longer used as a medicine for toothaches in general. (7)

If you compare the ingredients of clove oil vs Orajel, you will see they are entirely different things. Orajel uses 7.5% benzocaine, not eugenol.

There was a study which used an even higher concentration of benzocaine than Orajel, then pitted it against homemade clove gel and a placebo version. There were 73 people who participated and they were blinded as to what they were being given.

Five minutes after being treated, each person was poked with two needles. There was “significantly lower mean pain scores” for both the 20% benzocaine and the clove oil remedy groups, but not the placebo. (8)

While it may have some numbing effect, the oil is not used by dentists for tooth aches. Not too long ago, the FDA downgraded the effectiveness of eugenol. Today there is considered to be “insufficient evidence” of using it for that purpose. (4)

It’s not clear if the source is clove, but there is an OTC toothache medication kit that contains natural eugenol. The brand is Red Cross. We don’t know if it’s for sale at Walmart, Walgreens, and similar places, but you can get it on Amazon.

2. Pets

white cat with head upside downAdding some to a fish bowl is actually considered a humane way to euthanize fish, so clearly it is not safe for marine vertebrates! Reptiles like turtles and snakes, as well as amphibians like frogs, are also likely in danger.

So it kills fish, but might it do the same to your cat?

Essential oils safe to diffuse around cats and dogs are few and far between. Cats have insufficient amounts of a liver enzyme known as glucuronyl transferase, which is needed to breakdown certain compounds. Those include some which are found in essential oils like 1,8-cineole, camphor, limonene, ketones, phenols, methyl salicylate, and pinene. This laundry list of compounds encompasses most oils, including clove. It would be dangerous for your cat to eat, drink, or even breathe in the vapors. (9)

Clove oil is not safe for dogs to ingest, but since they don’t have the same enzymatic deficiency as cats, diffusing normal amounts around them is considered to be a safer practice.

Of course, many cat owners do diffuse clove and other oils around the house, with their kitties seemingly experiencing zero consequence. There is a big difference between air exposure and direct contact. Plus, the concentration in the air is a factor. The “red line” of how much is okay is ultimately not clear. If you want to be completely safe, you should not diffuse or use them around cats whatsoever.

3. Killing fleas

This is one of the specifc ways people are using it for pets. Safety concerns aside, does it work for repelling fleas?

In a survey of 60 small-scale organic farmers in Canada, using clove essential oil for fleas was not mentioned, but some highlighted its use for ear problems in dogs and cats. But so were more than a dozen other oils and there was no way to gauge safety or efficacy from the survey results. (10)

No one has studied clove or eugenol formally for this purpose. Even if it works for fleas, it seems like one of the more risky options. The popular remedy of peppermint oil hasn’t been studied and may not be safe either.

4. Herpes virus

viral or bacterial infection growing in Petri dishThere is a difference between something working in vivo (inside the body) and in vitro (outside the body).

There has been in vitro research – meaning in a lab – which has found that eugenol appears to decrease the replication rate of herpes (HSV-1 and HSV-2). In mice, it was also found to delay the viral development when used topically. In humans, eugenol or clove essential oil for herpes has never been studied. It should not be used for that purpose. (11)

5. Gum and canker sore pain

Can you put clove oil on gums? Using pure oil would be a bad idea but some gels containing it are sold for this very purpose. If a product is approved for this type of internal use, then yes very small amounts can be applied orally as per the instructions. Some brands of toothpaste and mouthwash make use of it too.

Although not a gel, Doterra’s instructions say to dilute only one drop in fractionated coconut oil and that can then be applied to the area desired. Doterra clove oil is vague as to what constitutes a permissible “desired area” topically. Does it include topically in the mouth? The brand Young Living has equally vague instructions. To be safe, you shouldn’t use those brands for gums.

Even if a product can be used, the efficacy and safety for use in gum pain and canker sores has not been clinically validated. Remember that Orajel (and the Dollar General knock-off) uses benzocaine. A gargle with clove oil mouthwash is something marketed for fresh breath and taste, not as a treatment for any pain. Using it for mouth sores of any kind should not be done without approval from your dentist or doctor.

6. Weed killer

weed growing in concreteFinding effective natural herbicides for organic farming can be a challenge. Vinegar is one of the most common natural chemicals used and some products are starting to make use of eugenol, such as Matran II by Ecosmart Technologies.

Penn State University tested a vinegar and clove oil weed killer. Both were found to have similar performance. In some ways, clove was even better as a natural herbicide:

  • More consistent results when treating velvetleaf.
  • 12 and 168 hours after application, it was more effective than vinegar.

The big problem with using this oil as a weed killer is that it’s too expensive. Sure, you highly dilute in water, but vinegar is such a cheap alternative that it remains preferred, even if it might be a less effective herbicide. (12)

7. Antibacterial

Methicillin-resistant Staphylococcus aureus (MRSA) is a very dangerous infection since it is resistant to conventional antibiotics. South Korean scientists tested eugenol against MRSA cultured in the lab and in vivo using live rats, by creating the infection in the middle ear of rats.

antibiotic effects of clove eugenol on different strains of MRSA infections

The compound was said to disrupt the membrane bilayer of the bacteria, which made if more permeable, causing the contents of those cells to leak. Due to this purported mechanism of how eugenol works, it “significantly decreases the colonization” in the tested ear infections and cultured bacteria biofilms. (13)

While there have been numerous studies suggesting that the essential oil of clove has antibacterial benefits, it’s never been studied in humans. Using it for UTI, skin infections, or any other type is not something you should do.

Reviews of Enessa clove oil for acne control may be positive, but there’s no related science on whether its effective against the bacteria Propionibacterium acnes (P. acnes).

8. Lyme disease

Despite what you may read elsewhere, there is zero research about Lyme disease and clove or eugenol.

The closest you will find is research about using it as a natural mosquito repellent, as a way to prevent insect bites which might harbor Lyme, malaria, dengue fever, Zika, and similar diseases. (14)

9. Candida antifungal

Candida albicans colony under microscopeCandida albicans is a fungus which wrecks havoc on the lives of many people without a cure. It can cause infections of the GI tract which never seem to stay away. It’s also the culprit in oral thrush and vaginal yeast infections.

In the NIH PubMed Database, you will actually come across a few dozen papers about the antifungal potential of eugenol. It has been tested against not just the common C. albicans species, but also C. parapsilosis, C. tropicalis, C. glabrata and others. (15)

There’s only one human study involving this compound. At 23 gynecological centers in Italy, a total of 459 patients participated. Roughly half used topical antibiotics for their vaginal candidiasis, while the other half used a douche containing eugenol and thymol (from thyme oil). It had “a similar significant symptom reduction” as the prescription antibiotic medicine. However this is only one study and it didn’t even use clove oil by itself.

10. Burns

Just as some people use it as a remedy for mouth sores and toothaches, you hear about some applying it to superficial injuries of the skin, such as a minor burn.

Will it numb the pain of that injury? Possibly. But clove oil burns, as in it might cause a burn too!

There have been a few published case studies of topical self-medication using the oil and it causing chemical burns. Especially with the mouth, since the mucous membranes are even more sensitive than skin. (16)

In short, there aren’t studies about clove helping the pain or healing of a burn, but there are papers about it causing them.

The take away is…

…that the oil should be used for what the manufacturer labels it for, not as a remedy for some health ailment. If you plan on using it for oil pulling, mouth wash, or toothpaste, make sure you use flavor or food grade clove oil. That’s different than therapeutic grade, which can only be used externally.

If it is marked for internal use, the dosage will likely be only a drop or two. Don’t exceed the directed amount. It’s too strong and side effects can result.

Where to buy

conventional vs. organic clove bud oil next to each otherWhere do you find clove oil in the grocery store? You won’t. Your standard supermarket – like a Kroger, Ralph’s, or Tesco – doesn’t carry essential oils. They will only sell clove spice powder.

If you’re looking for the clove oil location in Walmart, you’re going to be looking for a very long time! They only sell it on Walmart.com and Target doesn’t carry it either. CVS, Walgreens, Rite Aid and other pharmacies also shy away from selling EOs.

Whole Foods will have it, but watch out for the non-organic. Aura Cacia had an organic clove essential oil for sale, but the other stocked brands weren’t.

Brands like Now Foods, Young Living, and Enessa for acne control are only sold through specialty retailers.

If you just want a small and cost-effective bottle to try out, the USDA certified organic version from Plant Therapy is available on Amazon.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.