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Bad Breath: Causes and What Helps

Bad breath is common and usually starts in the mouth, so it can often be fixed at home. Here is what causes it, what actually helps, and when it is worth seeing a dentist or doctor.

Updated September 2026·By the OHA editorial team·6 min read·How we write
Key takeaways
  • Bad breath (halitosis) is very common and usually comes from bacteria in the mouth, so it can often be treated at home.
  • Brush twice a day with fluoride toothpaste and clean between your teeth every day. Some health bodies also suggest cleaning your tongue, though they disagree on how much it helps.
  • Gum disease, dry mouth, strong-smelling food, smoking and some medical conditions can all cause it.
  • Mouthwash and mints only mask the smell for a while and will not fix an underlying cause.
  • See a dentist if it does not improve after a few weeks of good cleaning. If your mouth is healthy, they may suggest seeing a doctor.

Most people worry about their breath at some point. The NHS describes bad breath, which doctors call halitosis, as very common and says you can usually treat it yourself. healthdirect Australia adds that it is normal to have bad breath when you first wake up, and that this usually goes once you have had a drink or cleaned your teeth. Breath that stays unpleasant through the day is worth looking into.

What causes bad breath?

Most bad breath starts in the mouth. The Oral Health Foundation explains that persistent bad breath is usually caused by smelly gases released by bacteria that coat the teeth, gums and tongue, and that bits of food caught between the teeth or on the tongue can also rot and smell. The Better Health Channel (Victoria) notes that halitosis is not infectious.

Not cleaning thoroughly enough

healthdirect says food left in the mouth is broken down by bacteria, which creates an unpleasant smell. It also says that plaque (a sticky build-up of bacteria) along the gumline lets bacteria grow, which can lead to gum disease as well as bad breath.

Gum disease and other dental problems

The NHS lists problems with your teeth or gums, such as gum disease, holes in your teeth or an infection, as causes of bad breath. The American Dental Association says bad breath that will not go away, or a constant bad taste in your mouth, can be a warning sign of advanced gum disease.

Dry mouth

Saliva helps wash the mouth clean. healthdirect explains that with a dry mouth the bacteria are washed away less often, so they build up, and that the mouth makes less saliva overnight, which is why breath is often worse in the morning. The NHS lists the main causes of a dry mouth as dehydration, some medicines, breathing through your mouth at night, anxiety and cancer treatment. A dry mouth that does not go away can sometimes be caused by a condition such as diabetes.

Food and drink

Strong-smelling foods such as garlic, onions and coffee affect your breath, as the American Dental Association and the Oral Health Foundation both note. The Better Health Channel says the effect of foods like these is short-lived. The NHS also lists fasting or crash dieting as a cause.

Smoking, vaping and alcohol

The NHS, healthdirect and the Oral Health Foundation all list smoking, and healthdirect also includes vaping and drinking alcohol. The American Dental Association points out that smoking affects your sense of smell, so smokers may not notice how their breath smells.

Dentures

healthdirect says bacteria on dentures can cause bad breath if they are not cleaned regularly. The NHS advises keeping dentures clean and taking them out at night.

Medical causes

Less often, the cause is outside the mouth. The sources list, between them:

  • tonsillitis and throat or chest infections
  • sinus problems, such as a sinus infection
  • acid reflux from the stomach
  • diabetes
  • liver or kidney disease (see kidney disease and oral health)

The American Dental Association says that if your dentist has ruled out mouth causes and you are brushing and cleaning between your teeth every day, you should see your doctor.

How can you tell if you have bad breath?

It can be hard to judge your own breath. The Oral Health Foundation suggests licking the inside of your wrist, waiting a few seconds and smelling it, or asking someone you trust to tell you honestly. It adds that noticing a strange taste in your mouth can be a sign.

What helps?

The NHS says the best way to make sure you do not have bad breath is to keep your teeth, tongue and mouth clean.

  1. Brush twice a day for 2 minutes with a fluoride toothpaste, gently along the gums.
  2. Clean between your teeth every day with interdental brushes or floss. The NHS says at least once a day. healthdirect goes further and suggests flossing twice a day.
  3. Clean your tongue gently. See the note below.
  4. Keep your mouth moist. Drink water regularly, and chew sugar-free gum to help make saliva, as healthdirect and the Oral Health Foundation suggest.
  5. Do not smoke, and do not drink too much alcohol (NHS advice).
  6. Keep dentures clean and take them out at night.
  7. Have regular dental check-ups, even if you feel fine.

If you have a dry mouth, the NHS suggests sipping cold water through the day and chewing sugar-free gum, and says a pharmacist can advise on gels, sprays and lozenges. Do not stop a prescribed medicine without advice first, even if you think it is causing your dry mouth.

Does cleaning your tongue help?

The health bodies do not agree. The NHS advises gently cleaning your tongue once a day with a tongue scraper or cleaner, and the Oral Health Foundation says it can help reduce bad breath caused by bacteria on the tongue, working gently from the back of the tongue towards the tip. healthdirect says tongue cleaning does not treat halitosis but can help remove bacteria from your mouth. The American Dental Association says there is no evidence that brushing or scraping your tongue prevents or improves bad breath, because the bacteria grow back quickly, and treats it as a matter of personal preference. The Oral Health Foundation stresses that tongue cleaning does not replace brushing and cleaning between your teeth.

What about mouthwash and mints?

They can help for a short time. The NHS suggests trying an antibacterial mouthwash or toothpaste. The American Dental Association says over-the-counter mouthwashes can kill bacteria or mask bad breath, but only temporarily. The Oral Health Foundation says mouthwash will not fix the problem if something else is causing it, and suggests talking to your dental team if you find you are using it all the time. healthdirect warns that mints can increase your risk of tooth decay if they contain sugar. The NHS advises not using mouthwash straight after brushing, and suggests sugar-free mints or gum after strong-smelling food and drink.

When to see a dentist or doctor

Start with a dentist, as most causes are in the mouth. healthdirect says your dentist will check your teeth, gums, tongue and throat, and may compare the smell of mouth breathing with nose breathing to work out whether the cause is elsewhere. Depending on what they find, they may clean your teeth professionally, treat a dental problem, or give antibiotics for a dental infection. If they think a medical condition is responsible, they may suggest you see your doctor.

healthdirect also recognises that bad breath can knock your confidence or make you anxious around other people, and suggests talking to your doctor if it is affecting your mental health or social life.

When to see a dentist
  • Bad breath does not go away after a few weeks of treating it yourself (NHS advice).
  • Your gums are painful, bleeding or swollen.
  • You have toothache or wobbly adult teeth.
  • You have problems with your dentures.
  • There are other changes in your mouth that worry you (healthdirect advice).
Get help urgently
  • A bad taste in your mouth can be a sign of a dental abscess (a build-up of pus from an infection). The NHS says to ask for an urgent dental appointment or contact NHS 111 if you think you have one, especially with intense pain, a swollen face or jaw, or a high temperature.
  • Get emergency medical care straight away if you are finding it hard to breathe, speak or swallow, have a lot of swelling in your mouth, or have a swollen or painful eye. In the UK the NHS says to call 999 or go to A&E.

Frequently asked questions

Why is my breath worse in the morning?

Your mouth makes less saliva overnight, so bacteria are washed away less often and build up. healthdirect says morning breath is normal and usually goes after you have a drink or clean your teeth.

Can bad breath be a sign of something serious?

Usually it is not, but it can be. Persistent bad breath or a constant bad taste can be a sign of gum disease, according to the American Dental Association, and less often it is linked to conditions such as diabetes, reflux, or liver or kidney disease. If your dentist finds no cause in your mouth, see your doctor.

Should I use mouthwash to get rid of bad breath?

Mouthwash can freshen your breath for a while, but it does not fix an underlying cause. If you want to use one, healthdirect suggests asking your dentist or pharmacist which is right for you, and the NHS advises not using it straight after brushing.

Sources

  1. Bad breath, NHS, accessed September 2026
  2. Halitosis (bad breath), healthdirect Australia, accessed September 2026
  3. Bad breath, Oral Health Foundation, accessed September 2026
  4. Cleaning your tongue, Oral Health Foundation, accessed September 2026
  5. Bad breath, American Dental Association (MouthHealthy), accessed September 2026
  6. Tongue scrapers and cleaners, American Dental Association (MouthHealthy), accessed September 2026
  7. Halitosis or bad breath, Better Health Channel, accessed September 2026
  8. Dry mouth, NHS, accessed September 2026
  9. Gum disease, NHS, accessed September 2026
  10. Dental abscess, NHS, accessed September 2026

This article is general information about oral health. It is not a diagnosis or a substitute for advice from a dentist or doctor who knows your situation. If you have pain, swelling, bleeding that does not settle, or a problem that is getting worse, see a dental professional. In an emergency, contact your local emergency service.

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