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Bad breath (halitosis)
Category: Head, Eyes, Ears, Nose & Throat · All head & senses symptoms
What it can feel like
Bad breath is an unpleasant odour from the mouth that persists beyond the usual morning breath. Most of it originates in the mouth itself — bacteria breaking down food debris on the tongue and around the teeth — rather than the stomach, which is a common misconception.
Possible causes
A symptom can have many causes, and most are not serious. The lists below group conditions this symptom can be associated with — common causes first. They are possibilities to discuss with a clinician, not a diagnosis.
Common causes
Bad breath can be associated with plaque, gum disease, a coated tongue, dry mouth, smoking, alcohol, strong foods, and fasting or low-carbohydrate diets.
Other possible causes
Persistent bad breath can be associated with tonsil stones, chronic sinusitis with post-nasal drip, dental abscesses, and, rarely, metabolic conditions — a sweet, fruity odour with diabetes emergencies, or a fishy odour with certain metabolic disorders.
Red flags — when to seek help promptly
- Bad breath with a dental swelling, toothache or bleeding gums — dental review
- Bad breath with one-sided nasal discharge in a child (possible foreign body)
- Bad breath with weight loss or difficulty swallowing
- Fruity-smelling breath with vomiting, abdominal pain or rapid breathing — emergency
What a clinician may do
A dentist will examine teeth, gums and tongue and address plaque and gum disease; an ENT review follows if tonsil stones or sinus disease are suspected. Most management is mechanical — tongue cleaning, interdental cleaning, hydration — plus treating the identified source.
Watch: related videos
Examination and clinical videos from the MedicalVideos.com library relevant to this symptom. Some clinical footage is graphic — that is the nature of a medical video library.
Frequently asked questions
Why doesn't mouthwash fix it?
Mouthwash masks odour briefly and alcohol-based versions dry the mouth, which can worsen the bacterial breakdown that causes it. Mechanical cleaning — especially of the tongue's back surface — plus treating gum disease is what actually reduces it.
Can bad breath come from the stomach?
Rarely. The gullet is normally closed, so stomach odours do not continuously escape. Reflux and stomach conditions contribute in a minority; the mouth, tongue and tonsils are the source in the great majority of cases.
Related symptoms — Head, Eyes, Ears, Nose & Throat
Browse the B section of the A–Z list or return to the Symptoms A–Z hub.