Types of Bad Breath Smells: What Your Breath is Telling

Dr. Malavi Sivakanesan (292322)
Wisdom tooth signs and symptoms
Oral Hygiene

January 14, 2025

Bad breath can definitely be embarrassing, and it’s easy to dismiss it by thinking, “I ate garlic today” or “I haven’t had enough water.”

While occasional bad breath can be linked to certain foods or dehydration, the type of smell your breath carries can sometimes be an important signal from your body. Rather than ignoring it, it’s important to understand that persistent or unusual odours might indicate an underlying health issue.

So, read on to learn about the different types of bad breath smells and what they could be signalling about your health.

Why Does Your Breath Smell?

Bad breath, or halitosis, typically happens because of poor oral care. There are also other possible causes. Bad breath that doesn’t go away or keeps coming back can point to a serious, underlying health condition. Examples of such include gastrointestinal disorders or systemic conditions like diabetes and kidney disease.

However, the chief contributor that makes your breath smell bad is sulfur-producing bacteria that are present in the throat and on the surface of the tongue. These bacteria break down proteins and release the volatile sulfur compounds (VSC) that are responsible for bad smells.

Types of Bad Breath and Their Potential Causes

The bad odour accompanying halitosis is often contingent upon its root cause. So here are the types of bad breath smells and their potential causes:

Sweet or Fruity Breath Smell

The bad breath that smells sweet or like fruit or even nail polish is a potential symptom of diabetes. If the diabetic is left untreated, it can lead to diabetic ketoacidosis and also contribute to your breath smell.

In addition to the systemic condition, low-carb diets and fasting also cause nail polish-like breath. These diets make your body burn fat for fuel, releasing a chemical called ketones. The ketone buildup eventually alters the way your breath smells.

Rotten Tissue Like Breath Smell

  • Poor Oral Care: Poor oral care can lead to problems like cavities, ulcers, lesions, and fistulas. These hollows can hold decaying food and release a rotting or garbage-like smell.
  • Medical Devices: Dentures, crowns, or any orthodontic devices that don’t fit right in your teeth can trap food in the gaps. This leads to food decay, bacterial growth, and bad breath.

The rotten tissue-like breath smell is primarily due to infection in your mouth, throat, and lungs. However, there are other factors contributing to this bad breath

Sour Breath Smell

The sour breath smell is caused by gastroesophageal reflux disease (GERD). In this condition, the muscle between your oesophagus and stomach doesn’t close properly, resulting in the regurgitation of stomach acid and partially digested food into your oesophagus, throat, or mouth.

Feces-Like Breath Smell

If your breath smells like faeces, it may be a symptom of bowel obstruction. In this condition, the flow of waste through your intestine is blocked, leading to a faeces-like odour on your breath. In addition to blockage, there are other symptoms like bloating, vomiting, nausea, cramping, and constipation.

Urine Breath Smell

A urine-like odour on your breath may indicate azotemia and uremia. This condition occurs if your kidney is damaged. It leads to kidney dysfunction and the buildup of waste products like urea in the blood, which is eventually broken down into ammonia in the saliva. This makes your breath smell like urine or ammonia.

Musty Breath Smell

Musty or mouldy breath is generally associated with liver disease, including cirrhosis, where it cannot effectively detoxify the substances in the blood.

This leads to the buildup of sulfur-containing volatile compounds, such as dimethylsulfide, in the bloodstream. These compounds are then exhaled through the lungs, causing your breath to be musty.

Maple Syrup Like Breath Smell

If your breath smells like sweet maple syrup, it may be an indicator of maple syrup urine disease. This condition occurs when your body is unable to metabolise these three types of amino acids: leucine, isoleucine, and valine.

As a result, these amino acids and their toxic byproducts build up in blood and urine, causing your breath to have a maple syrup or caramelised sugar-like smell.

Fish Like Breath Smell

Fishy-smelling breath is caused by an enzyme disorder called trimethylaminuria, also known as fish odour syndrome. This condition happens when your body is unable to break down the compound trimethylamine, which is responsible for stinky breath.

Consuming choline-rich foods and poor kidney or liver functioning are also contributing factors to fishy-smelling breath.

For tips on addressing and managing bad breath, check out our blog: How Do You Get Rid of Bad Breath?

Medical Causes of Severe Bad Breath

In addition to poor dental health, there are other medical conditions that cause halitosis. So here are a few medical causes of severe bad breath

Dry Mouth

Dry mouth, also known as xerostomia, is primarily due to insufficient saliva production. It can be caused by dehydration, smoking, alcohol, and the use of medical drugs. Saliva is critical to keep the mouth moist and to remove any food that remains in the mouth. Thus, without enough saliva, bacterial growth increases, leading to bad breath suddenly.

Gum Disease

Gum diseases such as gingivitis and periodontitis cause inflammation in your gums, damage your tissue, and lead to tooth and bone loss. This infection results in constant bad breath.

Head and Neck Cancer

Tissue damage, sore mouth, and infection are common symptoms of cancer and lead to bad breath. In addition to cancer, cancer treatments such as chemotherapy are also a contributing factor.

How to Prevent and Treat Different Bad Breaths?

Here are a few preventive care that can help you treat your different bad breath,

Follow Good Oral Hygiene Routine

Good oral care starts with proper brushing, which involves brushing twice a day for 2 minutes. Additionally, flossing twice every day is essential. Using mouthwash is also recommended, as it freshens your breath, and fluoride protects your teeth from decay.

Quit Tobacco Use and Alcohol

Both tobacco and alcohol can contribute to bad breath by drying out your mouth and causing unpleasant odours. Quitting or reducing the use of these substances can help maintain fresh breath and improve overall oral health.

Do Regular Dental Checkups

Visiting a dental hygienist London for regular cleaning at least twice a year is essential for oral care. Regular checkups help in the early diagnosis of your dental problems.

When to Seek Professional Help?

Bad breath may seem harmless at first, but chronic bad breath, or halitosis, can be a cause for concern. If your bad breath persists despite maintaining a good oral hygiene routine and making lifestyle changes, it’s time to consult a professional. Persistent halitosis could be a sign of an underlying medical condition that requires attention.

If you’re looking for a trusted and reliable clinic to address your dental concerns, look no further than Complete Smiles. They offer flexible payment plans, free consultations for selected treatments, and a friendly team that cares for even the most nervous patients.

Photo of Dr. Malavi Sivakanesan

Dr. Malavi Sivakanesan (292322)

Dr. Malavi Sivakanesan is the principal dentist and co-founder at Complete Smiles in Harrow, Greater London. She is responsible for establishing the Complete Smiles brand throughout the United Kingdom and Europe and has 5 successful practices under her strong leadership.