Bad breath (halitosis): why it happens and how to get rid of it
Reviewed by: Dr Lauras Smilgevičius, dentist
Bad breath, known medically as halitosis, is one of those problems people rarely want to discuss openly, even though it affects millions. Research suggests that around a quarter of adults experience persistent or recurrent bad breath at some point, and in roughly 80 to 90 percent of cases, the cause is inside the mouth.
At Miško Dental Clinic, we often remind patients of one important point: halitosis is not just a social embarrassment or a minor aesthetic issue. Most of the time, it is a sign that something in the mouth, or occasionally elsewhere in the body, deserves attention. The good news is that in almost every case, the cause can be found and the problem can be improved or solved.
What is halitosis and why does it happen?
Halitosis, from the Latin halitus, meaning exhaled air, is the medical term for a persistent unpleasant smell on the breath. It is important to separate two things: temporary morning breath, which disappears after brushing, and chronic halitosis, which remains through the day despite oral care.
The main culprits are volatile sulphur compounds, often shortened to VSCs. The three main types are hydrogen sulphide, methyl mercaptan and dimethyl sulphide. Together, they account for around 90 percent of the unpleasant-smelling compounds found in exhaled breath. They are produced by anaerobic bacteria that break down protein-rich debris in the mouth, such as food particles, dead mucosal cells and blood from inflamed gums.
The most important hiding place for these bacteria is the back of the tongue. Its rough surface, deep grooves and filiform papillae can hold very high bacterial numbers, sometimes up to 10¹⁰ microorganisms per square centimetre. Studies show that a fissured tongue can collect twice as many bacteria as a smooth tongue.
Morning breath or chronic halitosis?
Morning breath is a natural physiological phenomenon. During sleep, saliva flow drops significantly, the mouth dries out and bacteria quietly produce sulphur compounds overnight. Brushing the teeth and tongue, followed by a glass of water, usually settles it quickly.
Chronic halitosis is different. It lingers throughout the day, returns within a few hours after cleaning, and people around you may give subtle hints, or sometimes not-so-subtle ones, that something is wrong. This longer-lasting form deserves a proper assessment.
How can you check your own breath? Your sense of smell adapts to your own odour, so it is difficult to judge directly. Try a few simple tests: scrape a clean teaspoon over the back of your tongue, wait 30 seconds and smell the coating; lick the inside of your wrist, let the saliva dry for 10 seconds and smell it; or ask someone you trust. The tongue spoon test is usually the most useful because around 80 to 90 percent of odour molecules are produced at the back of the tongue.
Oral causes: where bacteria feel at home
Most cases of halitosis begin in the mouth. These are the places where bacteria most often settle:
- Tongue coating. A white or yellowish coating on the back of the tongue is a living bacterial community. It is one of the most commonly forgotten areas of oral hygiene.
- Gum disease. Gingivitis and periodontitis create deep spaces between the tooth and gum where bacteria grow without oxygen and produce particularly strong sulphur compounds.
- Dental tartar and plaque. Hardened dental tartar becomes a shelter for microorganisms, and an ordinary toothbrush cannot remove it.
- Tooth decay and pulp infections. A deeply damaged tooth with dead or infected pulp can produce a very distinctive unpleasant smell.
- Poorly fitting fillings, crowns or dentures. Their edges can trap food debris and bacteria.
- Dry mouth, or xerostomia. Saliva is the mouth’s natural cleanser. When saliva is reduced, bacteria have a much easier environment in which to grow.
- Partly erupted or impacted wisdom teeth. A gum flap can form around them, trapping food and bacteria.
Non-oral causes: when the smell comes from elsewhere
In around 10 to 15 percent of halitosis cases, the cause cannot be found in the mouth. This is called extra-oral halitosis, and it often requires help from another specialist rather than a dentist alone.
The mechanism is straightforward: many volatile substances enter the bloodstream, reach the lungs and are exhaled with the breath. This is why even a perfectly clean mouth does not always guarantee fresh breath.
| Cause category | Common conditions | Typical signs |
|---|---|---|
| Oral | Tongue coating, gingivitis, periodontitis, tooth decay, tartar, dry mouth | Bleeding gums, tongue coating, sensitivity, dry mouth |
| ENT area | Chronic sinusitis, tonsillitis, tonsil stones, polyps, post-nasal drip | Blocked nose, mucus in the throat, cough, smell from the nose |
| Digestive system | GORD or reflux, H. pylori infection, Zenker’s diverticulum | Heartburn, sour taste, burping, pain after eating |
| Systemic disease | Uncontrolled diabetes with ketoacidosis, liver failure, kidney disease | Fruity acetone smell, ammonia smell, fishy or musty smell |
| Lifestyle and medication | Smoking, alcohol, antidepressants, antihistamines, diuretics, fasting | Dry mouth, thicker saliva, tobacco odour |
It is useful to know that some conditions create recognisable breath odours. Diabetic ketoacidosis can cause a sweet, acetone-like smell; kidney failure may cause an ammonia-like smell similar to urine; liver cirrhosis can produce a heavy, musty or raw-meat smell, known as fetor hepaticus. These are less common but serious signs that should not be ignored.
Medicines that often dry the mouth
More than 400 prescription and over-the-counter medicines can reduce saliva flow. Common examples include antidepressants, especially SSRIs and tricyclics, antihistamines for allergies, diuretics, some blood pressure medicines, medicines for urinary incontinence, benzodiazepines and opioid painkillers. If you have been taking such medication for some time and notice dry mouth and bad breath, speak to your doctor about whether the dose can be adjusted, and ask your dentist about supportive measures.
How to get rid of bad breath: step by step
A lasting solution to halitosis is almost never one clever trick. It is careful home hygiene and, when needed, professional treatment.
1. Professional oral hygiene with a dentist or hygienist
This is usually the first and most important step. During professional oral hygiene, we remove tartar above and below the gum line, plaque and staining. One appointment is often enough to remove 60 to 70 percent of the causes of bad breath. We recommend it at least every 6 to 12 months, and more often if gum disease is present.
2. Proper toothbrushing twice a day
Brush for at least two minutes. A toothbrush with splayed bristles is no longer doing its job, so replace it every 2 to 3 months. An electric toothbrush with an oscillating or sonic head removes plaque more effectively than a manual brush, especially in harder-to-reach areas.
3. Daily interdental cleaning
The spaces between the teeth make up around 40 percent of the tooth surface. If you do not clean them, you are missing nearly half the job twice a day. Choose floss, interdental brushes or a water flosser according to the width of the spaces.
4. Tongue cleaning
This is one of the cheapest and often most effective tools against halitosis. For technique, read our article “Should you clean your tongue, and how should you do it?”.
5. Water before mouthwash
Alcohol-based mouthwashes can mask odour briefly, but over time they dry the mouth and may make the situation worse. If you do use a rinse, choose an alcohol-free product with zinc compounds or chlorhexidine for short courses when recommended. The best natural support throughout the day is plain water.
6. Diet and lifestyle
Garlic, onions, coffee, alcohol and fatty animal-based foods can leave traces not only in the mouth but also in the lungs via the bloodstream. Reducing excess protein and acidic products, choosing vegetables and fruit with a high water content, and drinking green tea, whose polyphenols can suppress sulphur compounds, all help gradually and sustainably.
“Patients are often surprised when I say that halitosis is a diagnosis, not a shame. We approach breath concerns as calmly as tooth sensitivity or replacing a filling. The most important thing is to find the real cause, not to hide the symptom with chewing gum.”
Dr Lauras Smilgevičius.
Home care and professional treatment: who does what?
| Area | What you can do at home | What the dentist does |
|---|---|---|
| Bacterial load | Brushing teeth and tongue, interdental cleaning, rinses where appropriate | Professional hygiene, ultrasonic removal of plaque and tartar |
| Gums | Soft toothbrush, gentle cleaning, interdental brushes | Treatment of gingivitis and periodontitis, cleaning of gum pockets |
| Teeth | Fluoride toothpaste, dietary changes | Treatment of decay, replacement of fillings, root canal treatment |
| Dry mouth | Water, sugar-free xylitol gum, moisturising sprays | Saliva stimulants, medication review advice, assessment |
| Non-oral causes | Track symptoms and see your GP | Referral to an ENT specialist, gastroenterologist or endocrinologist |
When should you see a dentist?
Do not wait until the problem becomes established. Book a dental appointment if:
- Bad breath lasts longer than 2 to 3 weeks despite improved hygiene;
- It is accompanied by bleeding, swollen or painful gums;
- Your mouth is constantly dry, your taste has changed, or you see a coating on the tongue;
- It hurts to chew or your teeth feel sensitive;
- The smell is unusual, such as ammonia, acetone or mustiness, which may suggest a systemic cause.
At Miško Dental Clinic, we first carry out a full mouth examination, assessing the gums, tongue coating and condition of fillings. If needed, we use X-ray diagnostics so hidden problems are not missed. If the mouth is healthy but the breath odour continues, we refer you to your GP or another specialist. Our philosophy is simple: treat the cause, not only the symptom. That is the only route to a lasting result.
The day before your appointment, avoid tongue cleaning and mouthwash. This lets the dentist see the natural condition of the mouth and helps us assess coating and inflammation more accurately.
Miško Dental Clinic’s approach to halitosis
For us, halitosis is not a question of embarrassment; it is a question of finding the right solution. Just as a forest path needs care so it is not overtaken by moss, the mouth needs consistent attention. Our role is not only to clean the teeth, but to show you how to create an environment at home where bacteria have fewer places to settle. A smile should be both beautiful and fresh, and a dental visit should feel calm, without guilt or lectures.
Frequently asked questions about bad breath
Does halitosis always mean poor oral hygiene?
No. Many people with chronic halitosis clean their teeth more carefully than the average patient. The cause may be deeper, in periodontal pockets, the back of the tongue, dry mouth or even a condition outside the mouth.
Will mouthwash solve the problem?
It can mask the smell briefly, but it does not solve the cause. Alcohol-based rinses often make things worse because they dry the mouth. If you want to use a rinse, choose an alcohol-free product with zinc or chlorhexidine, and treat it as an extra measure rather than the main solution.
Can bad breath come from the stomach?
Less often than people think. The stomach is usually separated from the mouth by a muscular valve in the oesophagus. However, reflux or GORD, H. pylori infection and Zenker’s diverticulum can allow odour to come from the digestive tract. In these cases, a gastroenterology consultation may be needed.
Why does bad breath return a few hours after brushing?
The problem is most likely tongue coating or gum pockets. Surface toothbrushing does not reach these areas. Try a tongue scraper and interdental brushes. If that does not help, it is time for professional hygiene and an examination.
Do probiotics help with halitosis?
Studies on oral probiotics, including Streptococcus salivarius K12 and M18, show modest but noticeable benefits: VSC levels may fall and the balance of oral bacteria may improve. They are an addition to hygiene, not a replacement. Speak to your dentist before starting them.
Why is breath worse in the morning?
During sleep, saliva flow can fall by up to 50 percent. A dry, warm environment gives bacteria ideal conditions to produce sulphur compounds overnight. Morning brushing, tongue cleaning and a glass of water usually restore balance quickly.
Can children have halitosis?
Yes. Common causes in children include a foreign body in the nose, tonsil stones, chronic inflammation of the nose or throat, and mouth breathing during sleep. If a child’s breath is persistently unpleasant, a dental and ENT assessment is worthwhile.
Can halitosis be cured permanently?
In many cases, yes, but it requires systematic care. If the cause was tongue coating and tartar, the situation can improve within a few weeks. If periodontitis or a systemic condition is involved, the path is longer, but a good result is still achievable. The key is not a one-off fix, but a daily habit.
If you recognised yourself or someone close to you in this article, do not wait for the problem to grow. Our dentists in Klaipėda will listen without judgement, find the cause and create a clear plan with you.
BOOK AN APPOINTMENT