Bad breath
Bad breath, or halitosis, affects most people at least occasionally, and in almost every case it can be dealt with at home.
On this page
Bad breath, or halitosis, affects most people at least occasionally, and in almost every case it can be dealt with at home. Morning breath, or breath after garlic or coffee, is not a problem and needs no treatment. This page is about the other kind: breath that persists through the day, does not clear after brushing, and makes talking to people at close range uncomfortable.
In the vast majority of cases it starts in the mouth
The smell is produced by bacteria living on the tongue, between the teeth and under the gum margin. They break down food debris and protein from saliva and release volatile sulphur compounds — that is the odour itself. So the question is not about the stomach, as people usually assume, but about where plaque has collected in the mouth.
The main sources:
- coating on the back of the tongue — the commonest cause and the most overlooked. The rear third of the tongue is rough, the coating clings there firmly, and a toothbrush rarely goes anywhere near it;
- dental plaque and tartar, particularly along the gum line and between the teeth, where a brush does not reach;
- cavities, broken-down teeth and roots, and the overhanging edges of old fillings and crowns, which trap food;
- gum inflammation: bleeding on brushing, a swollen red gum margin and, in periodontitis, deep pockets around the teeth housing the anaerobic bacteria that produce the harshest smell;
- a dry mouth: saliva constantly washes bacteria away, and when there is little of it the smell gets stronger;
- removable dentures that are not taken out at night and not cleaned properly.
What to do every day
The routine is simple and almost entirely mechanical.
- Brush twice a day for two minutes with a fluoride toothpaste, taking the brush gently along the gum margin.
- Clean between the teeth once a day with interdental brushes of the right size or with floss. This is a separate job that brushing does not replace, and it is usually exactly where the smell is hiding.
- Clean the tongue once a day with a scraper or the back of the brush, from the base forwards, without pressure, a couple of strokes. The gag reflex settles if you do not start too far back and do not do it straight after eating.
- Drink enough water through the day so that the mouth does not dry out.
- Brush dentures daily and leave them out overnight.
- See a dentist regularly rather than when something hurts: tartar comes off only in the surgery, and nobody spots their own cavities or gum pockets.
Judge the result after two or three weeks of this. If the smell is still there, the problem is not effort but a cause that needs finding.
Mouthwash, chewing gum and mints
These deserve a separate word, because they absorb the most money and deliver the least.
Mouthwash does not replace cleaning. The fragrance covers the smell for half an hour while the plaque stays exactly where it was. Antibacterial formulations do genuinely help, but as an addition to mechanical cleaning and usually for a defined period, not for years. Alcohol-based mouthwashes make a dry mouth worse, because they dry the lining further. If your mouth is already dry, choose an alcohol-free product.
Chewing gum and lozenges work by stimulating saliva, so they are not useless — but only the sugar-free kind: sugar feeds the same bacteria and damages teeth. Relying on them instead of solving the problem is a way of not noticing it for years.
What usually gets forgotten
- Medicines that dry the mouth. The list is long: antihistamines, many blood pressure tablets and diuretics, antidepressants, medicines for bladder problems, travel sickness remedies. If the smell and dryness started soon after a new prescription, say so — an alternative can often be found.
- Mouth breathing. A blocked nose, a deviated septum, adenoids in a child, snoring with the mouth open: the mouth dries out overnight and morning breath becomes strong and persistent.
- Smoking and vaping. They carry their own smell, dry the lining and markedly raise the risk of gum disease, which is itself the cause of a much harsher odour.
- Fasting and low-carbohydrate diets. The body switches to burning fat and a sweetish, acetone-like smell appears. This has nothing to do with hygiene; brushing will not shift it, and it goes when carbohydrate returns to the diet.
- Alcohol dries the mouth, and the smell of drink comes out through the lungs, so rinsing has no effect on it.
- Age and dehydration. Saliva production falls with age, and dryness worsens after a feverish illness, in hot weather and in dry indoor air.
When the cause is not in the mouth
If the teeth and gums are sound and the routine is in place but the smell remains, look further — starting with the nose and throat.
- Tonsil stones: whitish, crumbly lumps in the crypts of the tonsils with a very distinctive putrid smell. Common, and almost always missed.
- Chronic tonsillitis — and in a child, a foreign body up the nose that they will not mention, in which case the smell comes with discharge from one nostril.
- Sinusitis and post-nasal drip: mucus runs down the back of the throat and feeds bacteria.
- Acid reflux. Stomach contents come up into the oesophagus and throat; there is usually heartburn, a sour taste, a hoarse voice in the morning and a cough as well. Plain "stomach trouble", contrary to popular belief, does not cause bad breath: the oesophagus is normally closed.
Rarely the smell points to a general illness, and then it is fairly characteristic: sweet and fruity or acetone-like in uncontrolled diabetes, ammoniacal in severe kidney disease, sweetish and musty in severe liver disease. In all of these the breath is never the only complaint — thirst, weight loss, weakness, swelling or yellowing of the skin sit alongside it. Worth remembering separately is a breaking-down tumour of the mouth or throat, flagged by an ulcer that will not heal, a lump, pain on swallowing, or hoarseness lasting more than three weeks.
You cannot smell your own breath — and the reverse happens too
People adapt to their own smell and stop registering it, so checking yourself is nearly impossible. Cupping your hand does not work. Two things do: asking someone close to you outright, or running a clean spoon over the back of the tongue, letting it dry for half a minute and smelling it.
The opposite situation also exists: a person is convinced they smell, nobody around them confirms it, the dentist finds nothing, and yet they cover their mouth, avoid close conversation and chew gum constantly. This is halitophobia, an obsessive fear of one's own breath. It is distressing and narrows life considerably, but it responds well to help, and asking for that help is as reasonable here as for any other cause. Endless rinsing and new toothpastes do not touch it.
When to see someone about it
See a dentist if the smell persists for several weeks despite a proper routine; if the gums bleed, are swollen or sore; if there is toothache, a loose tooth, a chipped or broken-down tooth; or if a denture rubs or smells in itself.
See a doctor if the smell comes with a persistent sore throat, tonsil stones, a blocked nose and discharge from one side; with heartburn and a sour taste; or with marked thirst, weight loss, weakness or swelling. Do not put it off if there is an ulcer or a lump in the mouth that has not healed in three weeks, if swallowing has become difficult or painful, or if your voice has changed.
Online consultation
An online doctor can help work out where to go: to a dentist, to an ear, nose and throat specialist, or to a family doctor. They will go through when exactly the smell appears and what it comes with, look over your list of medicines for the ones that dry the mouth, and discuss whether anything can be swapped. They will weigh up the features that call for investigation and suggest which tests are worth doing. And if the issue is fear of a smell that is not there, they can help with that as well.
This material is for information only and does not replace medical advice.
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