Home Health 15 Types of Bad Breath Smells and Their Health Warnings
types of bad breath smells

15 Types of Bad Breath Smells and Their Health Warnings

by Martha Simmonds

Bad breath is just a fact of life sometimes. Sometimes you forget to brush your teeth before running out the door, or you eat a stinky meal full of onions. However, sometimes, bad breath can be something much more serious.

If you can identify what your bad breath smells like, or people often tell you what your breath reminds them of, you may be able to identify what is wrong. So here are 15 types of bad breath smells so you can help narrow down what may be causing your chronic bad breath.

Why You Have Bad Breath: 9 Reasons

Bad Breath

Bad breath can be caused by a variety of reasons. Some of them are serious and usually signal health conditions that need to be treated.

1. Disease
2. Infections
3. Smoking
4. Diet
5. Improper Oral Hygiene

Make sure you are eating healthily and taking care of your teeth, including brushing, flossing, and using mouthwash to reduce any bad breath.

However, it is important to note that the reasons above are causes of severe and consistent bad breath. If you have bad breath occasionally, there are common reasons for it.

6. You ate smelly foods
7. You just woke up and haven’t brushed your teeth yet
8. You drank something that had a strong smell
9. You haven’t brushed your teeth in a while

These are normal, and not a sign of something wrong with your body. It is when the smell persists for a few days that you should be worried, as that means something is going on with your body.

15 Bad Breath Smells and Their Possible Causes


1. Nail Polish Remover

Acetone, the main ingredient in nail polish remover can be released from the body when diabetes is present. This leads to breath smelling similar to nail polish remover.

Additionally, keto or low-carb diets can cause acetone-smelling breath as your body doesn’t have a quick-burning fuel and instead burns fats.

2. Acidic

Acidic breath often comes with people that have strong asthma or cystic fibrosis. This is because many people that have these conditions tend to breathe with their mouths, which increases the dryness in the mouth. The medication for asthma may also increase dryness.

The lack of saliva allows bacteria to grow in the mouth, which increases bad breath. Menstruating women may also have an acidic smell as they naturally produce less saliva around certain times of the month.

3. Musty

If your breath smells musty, this could signal a problem with the liver. Cirrhosis is the most common problem. The smell is usually a mix of sweet and musty, and it is due to the body trying to break down sulfur in amino acids.

4. Fruity or Sweet

Most often, when your breath smells sweet or kind of like fruits, diabetes is the most common reason. This is due to diabetic ketoacidosis, which occurs when your diabetes isn’t under control.

However, low-carb diets can also lead to a fruity and sweet smell due to the increased amount of ketones in your system.

5. Maple Syrup

Slightly different from just sweet, maple syrup breath can signal something entirely different. If you have maple syrup breath, it usually means that there are three amino acids you cannot metabolize, which are leucine, isoleucine, and valine.

If your earwax, urine, and breath all smell like maple syrup or sugar, it is often a sign of something known as maple syrup urine disease (MSUD).

6. Boiled Cabbage

Boiled cabbage smells on the break often occur when people have hypermethioninemia. This is a genetic disorder where the body struggles to or is unable to metabolize the methionine amino acid.

In addition to your breath, your urine will also often smell like boiled cabbage. However, most people don’t suffer any additional symptoms from this disorder.

7. Sour

Sour breath is most commonly associated with gastroesophageal reflux disease (GERD). This is when there isn’t a full closure between your esophagus and stomach. Often, this leads to your stomach acid and foods in your stomach coming back to your throat and mouth.

Your breath will often smell sour and like partially digested foods.

8. Feces

If your breath smells like feces, it usually means that you have a blockage that isn’t allowing you to expel your waste. On top of bad breath, you may also have problems like vomiting, cramping, constipation, and nausea.

Constipation and fecal-smelling breath in particular are good signs that something is wrong with your bowels. It is usually a good idea to visit a doctor if you haven’t used the bathroom in a few days.

9. Cheesy

If your breath smells cheesy, it usually means that your bad breath is actually coming from your nose. This usually means that you have some nasal leakage that drips down your throat, especially while lying down or sleeping.

10. Mold or Fungus

If your breath smells like mold, it is often due to an infection, microbial buildup, or growth. Sinus infections can also add to the smell if mucus sits in the back of the throat and microbes are allowed to grow in abundance.

11. Rotten or Decaying

If your breath constantly smells of rot or decay, it is often a sign of an abscess or an infection. Poor oral health often leads to this smell as you can get cavities and ulcers that smell, and food is more likely to stay in your mouth long enough to rot.

While the most common result is something wrong with your teeth, or rotting food stuck in between your teeth, there are other conditions as well.

An abscess in your mouth, throat, or lungs can lead to a fetid smell. Gum disease is another common issue. Granulomatosis is rare but also causes a rotten smell. It is an inflammatory disorder that can damage your blood vessels, nose, and kidneys.

12. Rotten Egg

Like with other rot smells, rotten egg smells usually mean that something is wrong with your digestive tract. This can be caused by GERD or a blockage.

13. Fishy

Fishy bad breath is often caused by an enzyme disorder that is characterized by your body being unable to break down the organic compound trimethylamine.

Not only will your breath smell like fish, but often your sweat and any other bodily fluid.

Another reason why your breath may smell fishy is kidney problems. If you have a lot of urea in your system, your breath may start to take on a fishy smell. This can be caused by diabetes as well, and can signal chronic kidney failure.

14. Ammonia or Urine

Diabetes and problems with the kidneys as a result can often smell like ammonia as well, instead of fish. Although it is the same condition, it may smell different for different people.

Sometimes, injury or disease can also cause damage to the kidneys that is accompanied by an ammonia smell. This is known as azotemia.

15. Sweaty Feet

The smell of sweaty feet on your breath is often caused by your body being able to break down vital proteins and amino acids. This usually means you have a lack of enzymes in your system.

If you notice the smell on an infant, they may have isovaleric acidemia. This is a genetic condition that causes a buildup of leucine in the body, specifically the blood.

How to Treat Bad Breath Smells


Making sure you are practicing proper oral health is very important. Clean any dental appliances you have like braces or dentures thoroughly. Also, floss at least once a day, and always brush your teeth at least twice a day.

Invest in a tongue scraper or make sure you thoroughly clean your tongue as well. Toss out tools like toothbrushes every few months to stop bacterial growth.

Also, make sure to visit your dentist regularly. They can help you identify when something is wrong. Keeping your mouth moist and having a good diet will also help.

For more serious conditions, you will have to work with a doctor to treat the problem first before your breath will improve.

When to See the Doctor

Any time you notice bad breath that sticks around for a long period is a good time to go to a doctor. This is because many bad breath smells are a sign of something more serious, like an undiagnosed disease, liver problem, kidney failure, or infection.

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