Bad Breath: What Causes It and How to Get Rid of It for Good

Bad breath (halitosis) is common, and most of it starts in the mouth, not the stomach. The good news is that it’s usually fixable with a better routine. Mints and mouthwash only hide it for a while.

Imagine leaning in to talk to a patient or a colleague and noticing them step back slightly. You’ve been chewing gum all day and brushing twice. But you’ve never cleaned your tongue, haven’t flossed in months, and you drink coffee instead of water through long shifts. Fixing those three things often makes the difference.

Common causes

• Bacteria on the back of the tongue and between teeth
• Gum disease and tooth decay
• A dry mouth, from not drinking enough, mouth breathing, some medicines, or long shifts without water
• Strong foods such as garlic, onion and spices
• Smoking and alcohol
• Crash diets and fasting, which can cause a fruity or “ketone” smell
• Dentures that aren’t cleaned properly

The routine that works

• Brush twice a day for two minutes with fluoride toothpaste
• Clean between your teeth daily with floss or interdental brushes
• Gently clean your tongue with a tongue scraper or your toothbrush, from back to front
• Drink water regularly, and chew sugar-free gum to boost saliva
• Clean dentures daily and take them out at night
• See a dentist and hygienist regularly

Mouthwash can help as part of a routine, but alone it only masks the smell.

But when is bad breath a sign of something else?

If your breath doesn’t improve after a few weeks of good oral care, see a dentist first, then a doctor. Bad breath can sometimes be linked to tonsil stones, sinus infections, acid reflux, or, less commonly, diabetes, liver or kidney problems. Get urgent help if your breath smells sweet or fruity and you also feel very thirsty, are peeing a lot, vomiting or confused, especially if you have diabetes, as this can be diabetic ketoacidosis.

Sources: NHS (Bad breath), American Dental Association (MouthHealthy), Oral Health Foundation, World Health Organization (Oral health). This guide is for general information and does not replace advice from your own nurse, doctor or dentist.