People usually associate strong-smelling breath with poor dental hygiene or a recent meal. However, 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 their 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 requires immediate medical attention.

This article will look at DKA, what to do if symptoms occur, and other possible causes of acetone-smelling breath.

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 found in some nail polish removers.

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.

Ketosis is when the body breaks down fatty acids for energy. As this happens, the liver releases ketones, including acetone, as byproducts.

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 ketone levels 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. This overproduction of ketones is what puts a person at risk for DKA.

DKA can cause the blood to become acidic and affect how the organs function. The condition usually occurs gradually, but if a person has been vomiting, it can develop quickly.

Symptoms of DKA

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

If symptoms progress without treatment, 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) advises people to not exercise if they have signs of DKA and to seek medical assistance immediately.

Learn more here about ketones, diabetes, and ketone testing.

A person may be at risk for DKA if:

  • They have type 1 diabetes.
  • They take a medication in the SGLT-2 inhibitor class of drugs (such as Jardiance or Invokana).
  • They do not take enough insulin for their needs.
  • They wake up with low blood glucose levels, which can sometimes happen overnight.
  • They do not take supplemental insulin when required, such as forgetting it or being unable to afford it.

Other factors that can increase the chances of developing DKA include:

  • 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 its 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 ADA suggests testing for ketones. This involves a urine test that a person can do at home.

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

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

A person should seek medical help right away if:

  • their breath smells strongly of acetone
  • other symptoms of DKA are present
  • a test shows that their 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 living with diabetes who has symptoms of DKA will likely need treatment in the hospital.

They will usually receive:

  • intravenous fluid replacement
  • intravenous insulin
  • monitoring and management of any electrolyte imbalance resulting from DKA

To prevent DKA, a person should:

  • use insulin and other medications as a doctor recommends and note any changes in their glucose levels or other symptoms
  • make lifestyle choices that help keep their blood glucose levels down, including diet and exercise modifications
  • learn the signs of a diabetes-related emergency and know what actions to take

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

A ketogenic diet

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

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

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

Studies suggest that the amount of acetone on a healthy person’s breath correlates with the rate of fat loss. 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 a keto diet should speak with a doctor first. It is not safe for everyone, including those with liver failure, pancreatitis, and individuals already living with high cholesterol.

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

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 a doctor for advice.

Other sources of acetone

Outside of 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 halitosis, or bad breath.

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.

A more recent abstract from 2014 also agrees with the effectiveness of using a breath test to screen for blood glucose levels.

Gum diseases, 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 living with diabetes whose breath suddenly has a fruity, acetone-like smell should check their blood sugar and ketone levels, as it could be a sign of diabetic ketoacidosis. Without treatment, DKA can quickly become a health emergency.

If a person’s ketone levels are high, they should 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.