One Clove in Your Coffee Every Morning? What the Science Really Says

Could a single clove turn your morning coffee into something more than a wonderfully aromatic drink? A video watched more than six million times has brought this simple kitchen ritual into the spotlight.

The research behind cloves is genuinely interesting. But what does it actually tell us about the coffee in your cup?

What the News Is Saying

On 16 September 2026, Dr Eric Berg published a YouTube video entitled 1 CLOVE in Your Coffee Every Morning (Here's What Happens).

By 9 October, it had attracted more than 6.1 million views, reflecting remarkable public curiosity about simple, inexpensive wellness habits.

Dr Berg describes adding crushed cloves to coffee and explores research into eugenol, the aromatic compound found in cloves. He introduces studies involving clove mouthwash in intensive-care patients, the stomach bacterium Helicobacter pylori, blood-glucose measurements and stomach ulcers.

These are worthwhile scientific questions, and the published research offers several interesting findings.

Our question is slightly different: what happens when someone crushes a clove, stirs it into coffee and drinks it as part of an everyday routine?

To answer that fairly, we need to distinguish what the studies actually tested from what remains unknown about the drink itself.

What is a clove — and why is eugenol interesting?

Cloves are the tiny, nail-shaped dried flower buds of the Syzygium aromaticum tree. They have been used for generations in cooking, from fragrant curries and rice dishes to warming drinks and festive baking.

Their flavour is unmistakable: aromatic, slightly sweet, warming and powerful.

Much of that character comes from eugenol, a compound found in clove essential oil.

Eugenol has attracted scientific interest because it demonstrates antimicrobial and antioxidant activities in experimental research. But a compound behaving in a particular way in a laboratory does not automatically mean that eating a small amount will produce the same effect inside the human body.

Whole cloves also differ from concentrated clove oil or standardised extracts. Those preparations can contain much greater or more precisely measured quantities of particular compounds.

Understanding this distinction makes the research easier to interpret.

What happens when you add a clove to hot coffee?

Dr Berg's suggested preparation is beautifully simple: crush a clove, add it to your coffee, allow it to steep for around two minutes and enjoy.

Crushing releases its distinctive aroma. Hot liquid can extract some of the spice's flavour compounds, creating a familiar, comforting drink with a different character.

But hidden inside this little kitchen experiment is an interesting scientific question:

How much eugenol actually enters the coffee?

Clove size, crushing, brewing temperature, steeping time and whether the solid spice is consumed may all influence exposure.

We have not identified a human clinical study establishing the effective eugenol dose delivered by one crushed clove steeped in ordinary coffee for two minutes.

That leaves us with two propositions:

• For flavour: adding a clove to coffee is a straightforward culinary experiment.
• For health: claims about improving blood sugar, digestion or preventing disease require clinical evidence involving relevant preparations and outcomes.

The first is enjoyable and practical. The second requires further investigation.

Does eugenol simply stay in the digestive tract?

The body's handling of eugenol is another interesting part of the story.

A published human metabolism study found that orally administered eugenol was rapidly absorbed and extensively metabolised. Less than 0.1% of the administered dose appeared unchanged in urine.

That does not mean less than 0.1% was absorbed or entered the bloodstream. It means very little was excreted in urine in its original, unchanged form.

The study therefore cannot be used to conclude that eugenol remains almost entirely in the stomach or that clove coffee mainly works locally in the digestive tract.

For readers interested in the original research, see The metabolism of eugenol in man.

Five health claims worth examining

1. Oral health: an intriguing clinical finding

One of the studies highlighted by Dr Berg investigated a specially prepared clove mouthwash in 168 mechanically ventilated intensive-care patients.

Researchers compared a 6.66% clove-extract mouthwash with 0.2% chlorhexidine mouthwash, applied twice daily for five days.

Ventilator-associated pneumonia was recorded in 20.2% of patients receiving the clove preparation, compared with 41.7% receiving chlorhexidine.

That is a substantial difference and a legitimate reason for researchers to investigate the preparation further.

However, these were seriously ill hospital patients receiving a defined oral-care intervention. They were not people drinking clove coffee.

What we can reasonably say: A particular clove mouthwash performed favourably in this trial. The result does not establish that clove coffee prevents pneumonia, treats gum disease or relieves toothache.

Read the original clove mouthwash clinical trial.

2. Stomach bacteria: promising laboratory research

Helicobacter pylori, often shortened to H. pylori, is a bacterium that can infect the stomach and contribute to gastritis and peptic ulcers.

In a published laboratory study, researchers tested eugenol against 30 strains of H. pylori. The compound inhibited bacterial growth under the experimental conditions.

This is useful early evidence of antimicrobial activity.

But bacteria growing in a laboratory are different from an infection inside a person's stomach. A potential treatment must reach the bacteria in appropriate concentrations, demonstrate safety and work reliably in human studies.

What we can reasonably say: Eugenol inhibited H. pylori in laboratory experiments. This does not establish that drinking clove coffee eradicates the infection or replaces prescribed treatment.

Explore the published H. pylori laboratory research.

3. Blood sugar: interesting, but a very small human study

The blood-sugar claim may be especially interesting to readers concerned about metabolic health.

Researchers conducted a pilot study involving just 13 volunteers aged 25 to 35, including ten men and three women.

Participants consumed 250 mg of a standardised, polyphenol-rich clove extract daily for 30 days. Researchers reported improvements in certain glucose measurements.

But the study was open-label, with no blinded placebo comparison. Its small size and limited participant population make it difficult to draw firm conclusions.

And importantly, the researchers tested an extract capsule — not whole cloves added to coffee.

What we can reasonably say: This preliminary human study provides a reason for further research into clove extracts and glucose regulation. It does not prove that clove coffee lowers blood sugar or treats diabetes.

Read the 2019 human clove-extract pilot study.

4. Stomach ulcers: an unexpected lesson about dose

Here is one of the more surprising findings.

Researchers studied eugenol in rats with experimentally induced stomach ulcers.

At a dose of 1 mg per kilogram of body weight, administered twice daily, eugenol accelerated healing. The researchers reported improvements of approximately 33% after seven days and 52% after fourteen days.

However, at a much higher dose of 100 mg per kilogram, twice daily for seven days, the ulcerated area increased by approximately 49%. An intermediate dose of 10 mg per kilogram did not significantly change the ulcer area.

This is fascinating because it challenges the assumption that more of a potentially beneficial plant compound must produce a better result.

Yet the experiment involved rats receiving measured doses of purified eugenol. It did not test people drinking clove coffee.

What we can reasonably say: Eugenol showed different effects at different doses in an animal ulcer model. These findings do not establish a beneficial or safe daily dose of whole cloves for humans.

Read the eugenol and gastric-ulcer research.

5. Antioxidants: what does this popular claim mean?

Cloves are often praised for their antioxidant properties, and there is a scientific basis for investigating them.

Eugenol can neutralise certain reactive molecules in laboratory experiments. Researchers have also observed antioxidant-related effects in experimental biological systems.

But laboratory antioxidant activity is not the same as demonstrating that a particular food or drink improves health outcomes.

The human body already possesses complex antioxidant-defence systems. Whether a specific dietary compound meaningfully changes disease risk depends on many factors, including absorption, metabolism, dose and clinical outcomes.

What we can reasonably say: Eugenol has antioxidant activity in experimental research. That does not prove that clove coffee reduces inflammation, slows ageing or prevents chronic disease.

What the research actually tested

Here is a useful way to see the evidence at a glance.

These findings are worth understanding, but they cannot be combined into a clinical recommendation that everyone should drink clove coffee daily.

What about coffee itself?

Coffee contributes another interesting dimension to the discussion.

Large observational studies have reported an association between regular coffee consumption and a lower risk of developing type 2 diabetes.

But observational studies cannot establish that coffee caused the difference. Coffee drinkers and non-drinkers may differ in ways that influence the results.

There is also a distinction between immediate and longer-term effects.

A systematic review of eight clinical trials, involving 247 participants, found that caffeinated coffee could temporarily produce less favourable glucose responses in short-term experiments. Some longer-term findings suggested potentially different effects.

These observations are not necessarily contradictory. A person's immediate response to caffeine is different from their long-term risk of developing diabetes.

Neither type of research establishes that adding cloves creates an additional blood-sugar benefit.

Read the systematic review of coffee and glucose metabolism.

What does this mean for me?

Perhaps the greatest attraction of Dr Berg's suggestion is its simplicity.

You do not need an expensive supplement or an elaborate routine to enjoy a familiar kitchen ingredient in a new way.

If you already like coffee and warming spices, a little clove flavour may make your morning drink more enjoyable.

But pleasure and medical treatment are different things.

If your real concern is persistent indigestion, an H. pylori infection, high blood glucose or another ongoing health problem, clove coffee should not replace appropriate assessment and care.

There is no need to turn every pleasant daily habit into a treatment plan.

How to try clove-flavoured coffee

Dr Berg suggests a straightforward method:

1. Lightly crush one whole culinary clove.
2. Add it to freshly prepared coffee.
3. Allow it to steep for approximately two minutes.
4. Enjoy the flavour, if it suits your taste.

This is the creator's suggested culinary method, not a medically validated dose or treatment.

You could also choose decaffeinated coffee if caffeine doesn't agree with you.

Use ordinary food-grade cloves, not concentrated essential oil. If the flavour is too strong or the drink causes discomfort, there is no reason to continue.

Who should be careful?

A modest amount of culinary spice and a concentrated herbal preparation can involve very different exposures.

Some circumstances deserve particular care.

People taking anticoagulant or antiplatelet medicines: Laboratory findings and medicinal clove-oil information raise potential interaction concerns. That does not establish that one clove in coffee creates a clinically important bleeding risk. Seek pharmacist or clinician advice before using concentrated or medicinal clove preparations.

People taking diabetes medicines: Do not assume cloves will improve glucose control or use them to replace medication. Discuss medicinal extracts with your healthcare team.

People sensitive to caffeine: Coffee can aggravate reflux in some people and may contribute to palpitations or disturbed sleep. Decaffeinated coffee may be preferable.

Pregnant or breastfeeding people, and children: Ordinary food use should be distinguished from medicinal preparations. Avoid introducing concentrated clove preparations without appropriate professional advice.

Concentrated clove essential oil should not be swallowed as a substitute for this recipe. Excessive ingestion has caused serious poisoning, including liver injury, particularly in young children.

The important principle is proportionate caution — not fear of an ordinary kitchen spice.

Next View Point

An important next research step would be a properly controlled human study comparing ordinary coffee and clove-flavoured coffee, using clearly defined clove quantities, preparation methods and clinically meaningful outcomes.

We will also watch for reliable measurements of how much eugenol enters coffee under typical brewing conditions.