Persistent bad breath is common, treatable, and almost always coming from somewhere specific in the mouth. Finding where is what fixes it: mints and mouthwash only cover it. Persistent bad breath most often starts in the mouth, from bacteria on the tongue and between the teeth, from gum disease or from dry mouth, and only occasionally from the throat, sinuses or stomach, so a dental exam and a thorough tongue and gum cleaning are the sensible first steps before anything else is tried.
Where it usually comes from
The large majority of cases originate in the mouth rather than the stomach, which is a persistent myth. Bacteria on the back of the tongue and in gum pockets produce sulfur compounds, and those are what you can smell.
A smaller proportion has a medical cause, which is why persistent bad breath that does not respond to dental treatment is worth raising with a physician.
Causes and what each needs
The order here roughly reflects how commonly each turns out to be the cause.
| Cause | Clue | What helps |
|---|---|---|
| Tongue coating | Visible film on the back of the tongue | Tongue cleaning, done gently and daily |
| Gum disease | Bleeding gums, bad taste | Gum treatment: masking will not touch it |
| Food trapping | Localized, worse near one tooth | Cleaning between teeth; fixing the trap point |
| Dry mouth | Worse on waking or on medication | Hydration, saliva substitutes, medication review |
| Decay or a failing restoration | One area, sometimes a bad taste | Restoring the tooth |
| Dentures not cleaned overnight | Worse in denture wearers | Daily cleaning of the denture and the tissue |
| Smoking | Persistent, plus staining | Stopping; it also drives gum disease |
| Medical causes | Persists after dental treatment | Assessment by a physician |
Why mouthwash is not the answer
Most mouthwashes mask odor for a period rather than removing its source, and strongly alcoholic ones can dry the mouth, which makes the underlying problem worse over time.
Cleaning the tongue and between the teeth changes more than any rinse. If it persists despite both, the cause needs finding rather than covering.
Common questions
What Causes Persistent Bad Breath: questions people ask
How do I know if I have bad breath?
Self-assessment is unreliable because you adapt to your own smell. Asking someone you trust is more accurate, and a dentist can assess the likely source.
Does bad breath come from the stomach?
Rarely. The overwhelming majority of persistent cases originate in the mouth. Reflux can contribute, but it is not the usual explanation.
Should I scrape my tongue?
Gentle daily tongue cleaning helps many people, since the back of the tongue is the most common source. Do not scrape hard enough to hurt.
Will a cleaning fix it?
It helps considerably if gum disease or heavy deposits are the cause. If it returns quickly, the cause has not been addressed. That is worth investigating rather than repeating.
My breath is bad only in the morning. Is that a problem?
Morning breath is normal: saliva flow drops overnight. Persistent bad breath through the day is the kind worth investigating.
Where does persistent bad breath usually come from?
The large majority of cases start in the mouth, not the stomach. Bacteria on the back of the tongue and in gum pockets produce sulfur compounds, and those are what you smell. A smaller share has a medical cause. Persistent bad breath that does not respond to dental treatment is worth raising with a physician.
What causes bad breath, and what helps for each cause?
Tongue coating needs gentle daily tongue cleaning. Gum disease needs gum treatment. Food trapping needs cleaning between teeth. Dry mouth needs hydration, saliva substitutes or a medication review. Decay or a failing restoration needs restoring. Dentures need daily cleaning. Smoking needs stopping. A cause that persists after dental treatment needs a physician.
Why is mouthwash not the answer?
Most mouthwashes mask odor for a period. They do not remove its source. Strongly alcoholic ones can dry the mouth, which makes the underlying problem worse over time. Cleaning the tongue and between the teeth changes more than any rinse. If it persists despite both, the cause needs finding, not covering.