A glass of water and soft toothbrush on a bathroom shelf

Quick answer

Persistent bad breath comes from bacteria breaking down protein in the mouth, most often on the back of the tongue, between teeth that aren't being flossed, under the gumline in gum disease, or around food traps like deep fillings and wisdom teeth. The fixes that work: clean between teeth daily, brush or scrape the back of the tongue, stay hydrated, and have gum disease treated professionally. Breath that stays bad despite two weeks of that routine warrants a dental examination, and occasionally a GP review for sinus, tonsil or reflux causes.

Where it actually comes from

  • The back of the tongue. The single most common source: a coating of bacteria producing sulphur compounds. It's why breath sprays fail; they perfume the air without touching the factory.
  • Between the teeth. Skipped flossing leaves protein rotting in the gaps. If the floss smells when you finally use it, that's the answer to the mystery.
  • Under the gumline. Gum disease creates pockets that brushing can't reach, with a characteristic persistent odour. This one needs professional treatment, not products.
  • Food traps. Broken fillings, deep cavities and partly erupted wisdom teeth hold debris in places you can't clean. Fix the trap and the smell goes with it.
  • Dry mouth. Saliva is the mouth's rinse cycle. Medications, mouth breathing, coffee and dehydration all reduce it, which is why morning breath is universal.

The two-week routine that settles most cases

  • Clean between every tooth once a day: floss or interdental brushes
  • Brush or scrape the back third of the tongue each morning (gag once, then it's easy)
  • Brush twice daily; spit, don't rinse
  • Water through the day; treat coffee as a dehydrator
  • Sugar-free gum after meals if your mouth runs dry
Mouthwash note: cosmetic rinses mask odour for an hour. If you use one, make it an adjunct after cleaning, not a substitute for it, and know that a rinse can't reach under the gumline where the stubborn causes live.

If two honest weeks don't fix it

Book an examination. We look for the specific sources home care can't resolve: gum pockets, failing fillings, trapped wisdom teeth, dry-mouth causes. Treating those is usually straightforward and the change is permanent rather than rented. Where the mouth checks out clean, the trail leads to sinuses, tonsils or reflux, and our co-located medical centre makes that referral a corridor, not a mission.

The part nobody says out loud

Most people with persistent bad breath don't know, and most who worry about it don't have it. If someone has hinted, don't be embarrassed into inaction; it's one of the most fixable problems we see, and the examination is judgement-free.