This is general patient information, not a diagnosis. Persistent bad breath that does not improve with good oral hygiene should be assessed.
Quick Answer
Most persistent bad breath, or halitosis, comes from the mouth itself. Bacteria break down food debris and proteins and release sulphur compounds, which smell. The main sites are the coating on the back of the tongue, gum pockets in gum disease, decay and broken fillings that trap food, food trapped around crowns, bridges and dentures, and a dry mouth, which allows bacteria to multiply. Brushing twice daily, cleaning between the teeth, cleaning the tongue, treating gum disease and decay, and keeping dentures clean resolve most cases. Mouthwash on its own usually only masks the smell. If the mouth is healthy and bad breath continues, causes outside the mouth, such as sinus, throat, reflux or some medical conditions, should be considered with a doctor.
Key Takeaways
- In most people, the source of persistent bad breath is in the mouth.
- The back of the tongue is a major and often overlooked source.
- Gum disease produces a characteristic odour and needs treatment, not mouthwash.
- Dry mouth, from medicines, mouth breathing or not drinking enough, makes bad breath worse.
- If the mouth is healthy and the smell persists, see a doctor.
Where Bad Breath Comes From
| Source | Why it smells | What helps |
|---|---|---|
| Tongue coating | Bacteria live in the grooves at the back of the tongue | Daily tongue cleaning with a scraper or brush |
| Gum disease | Bacteria in gum pockets produce sulphur compounds | Professional treatment of gum disease. See gum disease treatment |
| Decay and broken fillings | Food and bacteria trapped in cavities | Treatment of the tooth |
| Crowns, bridges, implants | Food trapped under or around them | Cleaning with floss, brushes or water flossers; check fit |
| Dentures | Plaque and debris on the denture | Clean daily, out of the mouth; remove at night if advised |
| Dry mouth | Less saliva to wash bacteria away | Treat the cause; drink water; sugar-free gum |
| Wisdom teeth | Gum flap over a partly erupted tooth traps food | Cleaning; assessment of the tooth. See wisdom tooth extraction |
| Foods, smoking, alcohol | Odours carried in the breath | Temporary; stopping smoking helps oral health generally |
A Simple Daily Routine
- Brush twice a day with fluoride toothpaste for two minutes.
- Clean between your teeth once a day with floss or interdental brushes.
- Clean your tongue from back to front.
- Drink water through the day, especially if your mouth feels dry.
- Clean dentures and appliances daily.
- Have regular check-ups and professional cleaning. See professional dental cleaning.
Dry Mouth
Saliva washes the mouth and controls bacteria. Many common medicines reduce saliva, as do mouth breathing, dehydration and some medical conditions. Morning breath is largely due to reduced saliva overnight. If your mouth often feels dry, tell your dentist and doctor; there are ways to manage it and protect your teeth, since dry mouth also raises the risk of decay.
When It Is Not the Mouth
If your teeth and gums are healthy and bad breath persists, other causes include sinus infection or postnasal drip, tonsil stones and throat infections, acid reflux, and, less often, other medical conditions. These need a doctor rather than a dentist. A dentist can tell you whether the mouth has been ruled out.
How to Tell If You Have Bad Breath
It is hard to smell your own breath. Asking someone you trust is the most reliable way. Licking the back of your wrist, letting it dry and smelling it gives a rough idea of the tongue's contribution.
Conclusion
Persistent bad breath is a symptom with a cause, usually in the mouth. Cleaning the tongue and between the teeth, treating gum disease and decay, and dealing with dry mouth fix most cases, and a dental check-up is the right place to start.
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