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People usually associate strong-smelling breath with poor dental hygiene or a recent meal. But it may reveal much more than that.

If a person’s breath smells like acetone — or nail polish remover — it may indicate that there are high levels of ketones in the blood. This may stem from diabetes, alcohol use, or dietary habits.

Whether a person has type 1 or type 2 diabetes, an acetone-like scent in the breath can indicate diabetic ketoacidosis (DKA), a potentially life-threatening complication that needs immediate medical attention.

This article will look at DKA, what to do if symptoms occur, and other causes of breath that smells like acetone.

Woman checking how her breath smells by holding her hand in front of her mouth.Share on Pinterest
A fruity or acetone smell on the breath can indicate DKA.

When a person has diabetes, their body either does not make enough insulin or it cannot use insulin effectively. Usually, insulin breaks down glucose in the blood so that it can enter the cells and provide energy.

If the body cannot get its energy from glucose, it starts burning fat for fuel instead. The process of breaking down fat for energy releases byproducts called ketones.

Acetone is a type of ketone, and it is the same fruity-smelling substance used in nail polish remover.

If the breath of a person with diabetes smells of acetone, this suggests that there are high levels of ketones in their blood. As the ketones build up, they increase the acidity of the blood. This can be toxic.

When the body breaks down fatty acids for energy, the process is called ketosis. As this happens, the liver releases ketones, including acetone, as a byproduct.

When the body is breaking down fat, the breath may smell sweeter, because the body is expelling acetone.

It is not usually harmful for the body to burn fat, as long as the levels of ketones in the blood do not become too high.

However, if there is too much glucose in the blood and too little in the cells — as can happen with diabetes — ketone levels can rise too high.

As a result, if glucose levels rise too high, the person is at risk of DKA. It can cause the blood to become acidic and affect how the organs function.

DKA usually occurs gradually, but if a person has been vomiting, it can develop quickly.

If a person’s breath smells very fruity or strongly of acetone, it can indicate DKA. Other symptoms of DKA include:

  • passing urine more often than usual
  • nausea and vomiting
  • abdominal pain
  • high blood sugar levels
  • breathing difficulties
  • confusion
  • dry or flushed skin

As symptoms progress, the person may lose consciousness and experience a coma. Without medical intervention, organ damage can occur. The effects can be life-threatening.

The American Diabetes Association (ADA) advise people not to exercise if they have signs of DKA but to seek medical assistance immediately.

Here, learn more about ketones, diabetes, and ketone testing.

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Keeping blood glucose levels within the target range can prevent DKA.

A person may be at risk of DKA if:

  • They do not take enough insulin for their needs.
  • They have an insulin reaction, as can sometimes happen overnight.
  • They do not take supplemental insulin when required, for example, due to forgetting or being unable to afford it.
  • They miss a meal or do not eat enough.

Other factors that can increase the chances of developing DKA:

  • having a cold or the flu
  • a lack of understanding about why and how to control blood sugar levels
  • a lack of awareness about DKA and the danger it poses
  • a heart attack, especially in older people with diabetes
  • the use of cocaine or other substances
  • pancreatitis
  • a stroke
  • the use of medications, including corticosteroids, some antipsychotic medications, and thiazide diuretics

Knowing about DKA and being able to recognize the symptoms can save a person’s life.

When the breath of a person with diabetes smells like acetone, they should check their blood sugar levels.

If a reading is above 240 milligrams per deciliter, the American Diabetes Association (ADA) suggest testing for ketones. This is a urine test that a person can do at home.

Ketone and blood glucose testing kits are available for purchase online.

The ADA recommend testing for ketones every 4–6 hours when a person is ill, for example, with a cold or the flu.

Seek medical help right away if:

  • The breath smells strongly of acetone.
  • Other symptoms of DKA are present.
  • A test shows that ketone levels are high.

If the breath of a person who does not have a diabetes diagnosis smells of acetone, they should see a doctor, who can check for diabetes and other causes of the smell.

A person with symptoms of DKA will likely need treatment in the hospital.

They will usually receive:

  • intravenous fluid replacement
  • intravenous insulin

To prevent DKA, a person should:

  • Use insulin and other medications as a doctor recommends and note any changes in glucose levels or other symptoms.
  • Make lifestyle choices that help keep blood glucose levels down, which may involve diet and exercise modifications.
  • Learn the signs of a diabetes-related emergency and know what action to take.

Various emergencies can arise if a person has diabetes. Learn more here.

Diabetes is not the only condition linked to breath that smells of acetone.

A ketogenic diet

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A keto diet is low in carbs.

Some people follow a ketogenic, or “keto,” diet, which contains:

  • a high level of fat
  • a moderate amount of protein
  • very few carbohydrates

This can force the body to break down fat for energy, rather than carbohydrates.

Studies have suggested that the amount of acetone on a person’s breath correlates with the rate at which they burn fat. If a person follows a ketogenic diet to lose weight, they may have a slight smell of acetone on their breath.

This type of diet is not suitable for everyone, and there may be adverse effects.

Short-term effects can include:

These may pass in a few days to a few weeks, but long-term unwanted effects are also possible, including:

Anyone thinking about trying the diet should speak to a doctor first, as it is not safe for everyone, including those with liver failure and pancreatitis.

While following the diet, a person should ensure that they consume enough liquids and electrolytes.

Here, learn more about low-carb, high-fat diets and whether they are a good option for losing weight.

Alcoholic ketoacidosis

A person who consumes large amounts of alcohol may not have a healthful diet or eat enough food to provide their body with energy.

In this case, the body may produce ketones, and a condition called alcoholic ketoacidosis may develop.

Symptoms include:

  • a smell of acetone on the breath
  • nausea and vomiting
  • abdominal pain

People with diabetes should limit their consumption of alcohol. Apart from the risk of alcoholic ketoacidosis, alcohol can cause spikes in blood sugar.

Alcoholic drinks can significantly boost a person’s overall sugar intake, especially if they include mixers such as sodas.

Anyone who finds it difficult to reduce their alcohol consumption should ask their doctor for advice.

Other sources of acetone

Outside the human body, acetone is present in:

  • paint thinners
  • nail polish
  • nail polish remover
  • plastic manufacturing processes

What is the difference between ketosis and ketoacidosis? Find out here.

Diabetes can also cause bad breath, or halitosis.

In 2009, researchers found that analyzing a person’s breath could help identify prediabetes, the early stage of diabetes. People who exhaled higher levels of carbon dioxide were more likely to have high blood glucose levels.

Gum disease, including gingivitis, can cause bad breath, but not breath that smells like acetone. Having diabetes can also make a person more likely to develop oral health problems.

Anyone whose breath has a fruity, acetone-like smell should check their blood sugar and ketone levels, as it could be a sign of DKA. Without treatment, DKA can quickly become a health emergency.

If ketone levels are high, seek immediate medical treatment. Doing so can prevent a life-threatening situation.

Wearing medical identification can help others know what to do in an emergency related to diabetes.