Why Do I Have Bad Breath? Causes & More

By Terez Malka, MD
Medically reviewed checkmarkMedically reviewed
June 9, 2022

If you’ve ever suffered from bad breath, you know how embarrassing and uncomfortable it can be.

Or if you’re talking to someone and you notice that they have bad breath, chances are you politely back away. 

Bad breath, or halitosis, is a common problem that can ruin your social life and make it difficult to communicate with other people.

But what causes bad breath in the first place? And what can you do to get rid of it? In this post, we’ll explore the causes of bad breath and some steps you can take to get relief.

What Is Halitosis (Bad Breath)?

Halitosis is defined as an unpleasant mouth odor that can result from a buildup of bacteria in the mouth, poor oral hygiene, or certain foods.

While most people think of bad breath as simply an unpleasant smell, it can also be accompanied by other symptoms, such as a bitter taste in the mouth, dry mouth, or a burning sensation in the throat.

Bad breath is a more common problem in adults than in children.


There are myriad potential causes of bad breath, including something as simple as dry mouth to more complex causes, like gastrointestinal issues. 

Certain foods

Eating foods like garlic, onions, and spicy dishes can cause bad breath.

This is because these foods contain sulfur-containing compounds that are released into the air when you breathe. The odor of these compounds can linger in your mouth for hours or even days after you eat them.

Other common foods that can cause bad breath include:

  • Cheese
  • Pastrami
  • Certain spices
  • Orange juice or soda
  • Alcohol

Poor oral health

If you don’t brush and floss daily, food particles remain in your mouth, causing bad breath.

A colorless, sticky film of bacteria (plaque) forms on your teeth. If not brushed away, plaque can irritate your gums and eventually form plaque-filled pockets between your teeth and gums (periodontitis).

Your tongue also can trap bacteria that produce odors. Lastly, dentures that aren’t cleaned regularly or don’t fit properly can harbor odor-causing bacteria and food particles.


Bacteria break down food particles trapped in the teeth or mouth.

The combination of the bacteria and decaying food in your mouth produces an unpleasant odor.

Brushing and flossing regularly removes trapped food before it decays.

Oral disease 

Oral diseases like gum disease (gingivitis), tooth decay, and abscessed teeth can cause bad breath.

These diseases cause a build-up of bacteria in the mouth that can lead to an unpleasant odor.

Dry mouth

Dry mouth can also occur if you don’t create enough saliva. Saliva helps keep your mouth clean and reduces odor.

Dry mouth can be a problem if you have a salivary gland condition, sleep with your mouth open, or take certain medications, including those that treat high blood pressure and urinary conditions.

Tobacco products

Smoking tobacco products can cause bad breath. This is because tobacco products contain chemicals that are released into your mouth and throat when you smoke.

These chemicals can cause an unpleasant odor. In addition, smoking tobacco products can also lead to gum disease and tooth decay, both of which can cause bad breath.


Bad breath can be caused by surgical wounds after oral surgery, such as tooth removal, or as a result of tooth decay, gum disease, or mouth sores.


People with diabetes are more likely to have bad breath due to high levels of sugar in the blood. 

This can lead to a build-up of bacteria in the mouth.

Gastrointestinal disorders

Gastrointestinal disorders like gastritis, GERD, and ulcers can cause bad breath.

This is because these disorders can cause a build-up of stomach acids in the mouth. The acids can then be exhaled, causing an unpleasant odor.

Certain medications

Certain medications can reduce saliva and therefore increase odors. Other drugs can produce odors as they break down and release chemicals in the breath.

Examples include nitrates used to treat angina, some chemotherapy chemicals, and some tranquilizers, such as phenothiazines. 

People who take vitamin supplements in large doses can also be prone to bad breath.

Other causes

Diseases, such as some cancers, and conditions such as metabolic disorders, can cause a distinctive breath odor as a result of the chemicals they produce.

Chronic reflux of stomach acids (gastroesophageal reflux disease, or GERD) can be associated with bad breath. 

Bad breath in young children can be caused by a foreign body, such as a piece of food, lodged in a nostril.

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A dentist or a healthcare provider may simply smell the breath of a person with suspected halitosis and rate the odor on a six-point intensity scale.

The dentist may scrape the back of the tongue and smell the scrapings, as this area can often be a source of the aroma.

There are a variety of sophisticated detectors that can rate odor more precisely.

They include the following:

  • Halimeter: This detects low levels of sulfur.
  • Gas chromatography: This test measures three volatile sulfur compounds: Hydrogen sulfide, methyl mercaptan, and dimethyl sulfide.
  • BANA test: This measures levels of a specific enzyme produced by halitosis-causing bacteria.
  • Beta-galactosidase test: Levels of the enzyme beta-galactosidase have been found to correlate with mouth odor.

Your dentist or oral health provider will then be able to identify the likely cause of the bad breath.


Treatment options for bad breath range from home remedies to more involved medical options.

Home remedies

There are a number of home remedies that can help to freshen your breath and reduce bad breath. 

These include:

  • Brushing and flossing regularly
  • Scraping your tongue
  • Avoiding tobacco products
  • Drinking plenty of water
  • Chewing sugarless gum or sucking on sugar-free candy that contains xylitol
  • Using mouthwash
  • Eating yogurt or other probiotic-rich foods
  • Avoiding foods that cause bad breath, such as garlic, onions, and spicy foods

Medical care

If home remedies do not work, or if you have a more serious condition, you may need to see a dentist or doctor. Treatment will depend on the cause of your bad breath.

If you have gum disease, your dentist will clean your teeth and remove any plaque or tartar. They may also recommend special mouthwashes or toothpaste.

If you have an infection, your dentist or medical provider will prescribe antibiotics.

If you have a condition like GERD, they may prescribe medication to reduce stomach acids.


There are a number of things you can do to prevent bad breath, including:

  • Brush your teeth at least twice every day using fluoride toothpaste. Be sure to brush along the gumline, as well as all tooth surfaces. Each time you brush your teeth, use your toothbrush to clean the surface of your tongue.
  • Floss your teeth at least once a day to remove food from between your teeth.
  • Eat fruits and vegetables every day.
  • Avoid foods that cause you to have bad breath. Also try to avoid alcoholic beverages, which often cause bad breath.
  • Avoid using tobacco products.
  • Most mouthwashes do not have a long-lasting effect on bad breath. If you use a mouthwash, swish it around in your mouth for 30 seconds before spitting it out.
  • If you wear removable dentures, take them out at night.
  • See your dentist twice a year to have your teeth cleaned.

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When To See a Medical Provider

You should see your dentist or doctor if:

  • Your bad breath does not go away with home treatment
  • Your bad breath gets worse
  • You have other symptoms like a sore throat, earache, or toothache
  • You have white patches on your tongue or inside your cheeks
  • You have a dry mouth
  • You have a bitter or sour taste in your mouth
  • Your gums are red, swollen, or bleeding
  • Your teeth are loose
  • You have trouble swallowing
  • You have pain when you chew food

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How can you get rid of halitosis?
The best way to get rid of halitosis is to practice good oral hygiene. This means brushing your teeth at least twice a day, flossing at least once a day, scraping your tongue, and using mouthwash. You should also avoid tobacco products and eat plenty of fruits and vegetables.
What is the major cause of halitosis?
There are many possible causes of halitosis, but the most common cause is poor oral hygiene. Other possible causes include gum disease, infection, dry mouth, and certain medical conditions.
Does halitosis ever go away?
In most cases, halitosis can be treated with good oral hygiene. However, if the cause of your halitosis is a medical condition, you may need to see a dentist or doctor for treatment.
How do you know if you have halitosis?
The best way to know if you have halitosis is to ask a friend or family member if they notice anything different about your breath. You can also try using a breath mint or mouthwash to see if your bad breath goes away. If your bad breath does not go away with home treatment, you should see your dentist or doctor.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Terez Malka, MD

Dr. Terez Malka is a board-certified pediatrician and emergency medicine physician.

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