Key points in brief
- Bad breath even after brushing usually comes from inside the mouth. Most often the source is a coating on the back of the tongue or bacteria around inflamed gums, in places a toothbrush does not reach.
- What helps depends on where the smell comes from. When your gums bleed, cleaning your tongue alone is usually not enough, and you need professional teeth cleaning or gum treatment.
- Clean your tongue and the spaces between your teeth every day. A mouthwash can ease the smell for a while, but it does not remove its cause.
- If the dentist does not find the source of the smell in your mouth, start with your family doctor. A smell of acetone in a person with diabetes, or in someone with severe thirst, vomiting or drowsiness, needs immediate medical help.
- It is hard to judge your own breath, so if the smell worries you despite daily cleaning, a dentist or hygienist can assess it more reliably. Sometimes the examination shows that your breath is normal.
Consult your case with an expert and get your treatment plan
How the dentist or hygienist examines you
When you have bad breath even after brushing, the dentist or hygienist first looks for the source of the smell in your mouth. Doctors call persistent bad breath halitosis. To begin with, the dentist asks how long the smell has been there, when it is strongest, what medicines you take, whether you smoke and whether your mouth gets dry.
Next, the dentist assesses your breath by smelling it at close range. Sometimes the dentist also uses a device to measure the sulphur compounds that cause this smell. The measurement and the assessment by smell do not always agree, so the dentist takes both into account.
After that, the dentist looks at your tongue, teeth, fillings and crowns, and uses a thin probe to measure the pockets, that is, the gaps between the tooth and the gum that deepen when the gum is inflamed. The dentist also checks which areas bleed. If you notice the smell in only one place - for example around a crown - read the article on why floss catches and smells unpleasant around a crown.
Sometimes a person is convinced they have bad breath, but the examination does not confirm it. Usually it is then enough for the dentist to go through the result and show how to look after the teeth and tongue. If the worry persists despite a normal result, what helps is a conversation with a psychologist or psychiatrist, not yet another mouthwash.
Four places you can check before your visit
A few observations made at home will help the dentist find the source of the smell more quickly. Check:
- your tongue: whether there is a white or yellowish coating on the back of it, closer to the throat;
- your gums: whether they bleed when you brush or floss, and whether they are red;
- the spaces between your teeth: whether the floss smells unpleasant after you pull it through, and whether food keeps getting stuck in one place;
- your saliva: whether your mouth gets dry, especially in the morning, and whether the smell got worse after you started a new medicine.
Bleeding gums, or floss that smells unpleasant after you pull it through, are a reason to see a dentist or hygienist. In people who smoke, the gums often bleed less, so the absence of bleeding does not rule out gum disease. Write down what you notice and mention it at your appointment.
Before the visit, ask the practice how to prepare. You are usually asked not to use mouthwash, chewing gum or perfume on the day of the visit, because they mask the smell.
The most common causes of bad breath
In roughly 8 to 9 out of 10 people with confirmed bad breath, the source of the smell is in the mouth. A toothbrush cleans the surfaces of the teeth well, but it does not reach the back of the tongue, the pockets along the gums or all the spaces between the teeth. So bad breath even after brushing twice a day is nothing unusual.
The dentist checks the possible sources one by one and often finds more than one. A cause outside the mouth is usually looked for only when no source in the mouth explains the smell:
| Where the dentist looks | What points to it | What usually helps |
|---|---|---|
| 1. Tongue | a thick white or yellowish coating on the back of the tongue | cleaning the tongue every day |
| 2. Gums | bleeding, swelling, tartar along the gums, deeper pockets when measured | professional cleaning and, with periodontal disease, treatment of the pockets |
| 3. Teeth and restorations | a cavity, a leaking filling or crown, a place where food gets stuck, a denture worn at night | treating the cavity, repairing the filling or crown, denture hygiene |
| 4. Saliva | dry mouth, medicines that dry the mouth | drinking water more often, talking to the doctor treating you about your medicines |
| 5. Outside the mouth | the examination at the practice does not explain the smell, or treatment brings no improvement | a visit to the family doctor, who refers you to an ENT specialist if needed |
Periodontal disease is a long-term inflammation of the tissues that hold the teeth in place. Bad breath is found more often in people with this disease than in people with healthy gums. Research also suggests that bacteria from the pockets along the gums spread to the tongue. That is why, when the gums are inflamed, cleaning the tongue alone is usually not enough. However, not everyone with periodontal disease has bad breath. So the absence of a smell does not mean that the gums are healthy.
Apart from the tongue and gums, places that are hard to clean yourself also give off a smell: crowded teeth, a poorly fitting crown or bridge, and fixed braces. The source can also be a dead tooth, a deep cavity that exposes the inside of the tooth, inflamed gum around an erupting wisdom tooth, or inflammation around an implant. Ulcers and other changes in the lining of the mouth can also be a source of the smell - a change that does not heal within 2–3 weeks needs to be shown to a doctor.
Halitosis treatment at the dentist: when professional cleaning is enough
Professional cleaning helps when the smell is linked to plaque and inflamed gums, which usually come with tartar. During professional teeth cleaning, tartar is removed with ultrasound, which is called scaling. Next, the teeth are air-polished to remove surface deposits, and finally they are polished and fluoride is applied. At Modern Dental & Orthodontics, the procedure is carried out by a dental hygienist as part of the dental hygiene and whitening service. The hygienist can also show you how to clean your tongue and the spaces between your teeth.
The effect generally lasts if you clean your tongue and the spaces between your teeth every day. Without this, the coating and plaque build up again and the smell returns. Guidelines recommend brushing your teeth at least twice a day and also using dental floss or interdental brushes and a tongue scraper every day. It is not known exactly how much daily tongue cleaning or a mouthwash reduces the smell over a longer period. So the dentist assesses the effect at a follow-up visit, after a few weeks of daily cleaning.
Professional cleaning alone is not enough when the inflammation has spread from the gum deeper, to the tissues that hold the tooth in place. In periodontal disease, bacteria live in the pockets below the gum, and professional cleaning does not reach them there. The pockets then need to be treated, which means cleaning them thoroughly below the gum, usually with a local anaesthetic. After this treatment, bad breath usually lessens.
Dry mouth, diet and habits
When the mouth is dry, bad breath even after brushing happens more often. There is less saliva in the mouth at night, which is why breath tends to be at its worst in the morning. The same can happen after a long gap between meals. Doctors consider this kind of smell normal, just like the smell after garlic, onion or alcohol.
Too little saliva is often a side effect of medicines, for example those used for high blood pressure, depression, anxiety, allergies and pain. If your mouth started to feel dry after a new medicine, tell the doctor who prescribed it. Do not stop taking the medicine on your own. If your mouth has been dry for a long time, read the article on dry mouth from medication.
If you have little saliva, drink water more often during the day. The doctor may also suggest a saliva substitute. Smoking makes bad breath worse, partly because it reduces the amount of saliva. A denture worn at night also encourages the smell: less saliva is produced at that time, and bacteria collect in the denture material. If you wear a denture, take it out at night and clean it every day.
Chewing gum, mints and cosmetic mouthwashes mainly mask the smell, and their effect is short-lived. If you also have inflamed gums, read which mouthwashes for gingivitis help, according to research.
When further tests are needed
If the dentist has not found the source of the smell, or treatment in the mouth has not helped, start with your family doctor. Tell the doctor what the dentist checked and how well the treatment worked. Roughly one in ten confirmed cases of bad breath has its source outside the mouth, most often in the nose, sinuses, tonsils or airways. If you clearly notice the smell from your nose, have a long-lasting runny nose or can see white lumps on your tonsils, known as tonsil stones, the doctor may refer you to an ENT (ear, nose and throat) specialist.
Less often, the cause is a digestive disease or a condition affecting the whole body, such as diabetes or kidney or liver disease. In such conditions, unpleasant-smelling compounds circulate in the blood and are breathed out through the lungs, so cleaning your teeth will not remove them. A smell linked to a whole-body condition is usually not the only symptom - the doctor then also asks how you feel and about your weight, thirst and other complaints.
Contact a doctor urgently, ideally the same day, if bad breath comes with:
- a smell like acetone or fruit in a person with diabetes, and also in anyone who has severe thirst, vomiting or drowsiness at the same time - call 112 or go to a hospital emergency department;
- a fever with a severe sore throat, swelling on one side or difficulty opening your mouth;
- difficulty swallowing, undigested food coming back up, or weight loss without an obvious cause;
- an ulcer or other change in the mouth that does not heal within 2–3 weeks;
- coughing up foul-smelling phlegm or blood.
If any of these symptoms comes with shortness of breath, call 112.
What to do if you have bad breath even after brushing
Start by cleaning your tongue and the spaces between your teeth every day. If your gums bleed, the floss smells unpleasant after you pull it through, or the smell worries you despite daily cleaning, have your breath checked by a dentist or hygienist. The examination will show whether professional cleaning is enough or whether your gums or teeth need treatment. If there is no source of the smell in the mouth, the next step is your family doctor and, if needed, an ENT specialist.
Frequently asked questions
Does mouthwash cure halitosis?
Mouthwash does not cure halitosis, but it can reduce or mask the smell for a while. Mouthwashes with chlorhexidine or cetylpyridinium chloride reduce bacteria, and zinc binds sulphur compounds. Chlorhexidine works most strongly, but with longer use it stains the teeth and can affect taste. It is used for a short time, on a dentist's or doctor's advice.
Does tartar cause bad breath?
It is not known whether tartar itself gives off a smell. The smell is more likely linked to plaque and inflamed gums, which usually come with tartar. Plaque builds up easily on rough tartar, and a toothbrush does not remove tartar. Removing tartar makes sense as part of professional cleaning or gum treatment, together with cleaning your tongue every day.
How do I clean my tongue properly?
Clean your tongue once a day, preferably with a tongue scraper, because it generally reduces the smell from the tongue better than a toothbrush. Move it gently from the back of the tongue towards the tip, a few times, without pressing hard. At first you may gag, but this usually eases with regular cleaning. A single cleaning freshens your breath only briefly, so it makes sense as a daily habit.
Can bad breath come from the stomach?
It can, but this is rare. Bad breath is sometimes linked to reflux or to infection with the bacterium Helicobacter pylori, but this link is less certain than for causes in the mouth. So the tongue, gums and teeth are checked first. A doctor decides on stomach tests, usually when you also have heartburn, stomach contents coming back up, or abdominal pain.
When should I see a periodontist?
It is worth seeing a periodontist, a dentist who specialises in gum disease, when your gums bleed despite careful brushing, when they recede, or when your teeth start to feel loose. Your dentist may also refer you to one if they find deeper pockets when measuring. A consultation also makes sense when the smell keeps coming back despite professional cleaning and daily tongue cleaning.
How long does the improvement last after professional cleaning, and when can the smell come back?
The improvement usually lasts as long as you clean your teeth, the spaces between them and your tongue every day. If your gums start bleeding again when you brush, this is a sign that the smell may come back. Check-ups with professional cleaning are usually recommended every 6–12 months. After treatment of periodontal disease, the interval is set individually, from 3 to 12 months.
What will you notice in the first week after gum treatment?
In the first few days, your gums may be tender and bleed slightly, and your teeth may be sensitive to cold. Serious problems after the pockets have been cleaned are rare. The full effect is assessed later. About 4 weeks after gum treatment, non-smokers usually rate their breath as better. Report increasing swelling, pus or a fever to the practice the same day.
Read more:
- Dental Hygiene and Whitening in Warsaw
- Professional teeth cleaning: What the procedure involves, does it hurt and what results does it deliver?
- Periodontitis: Symptoms, causes and modern treatment methods. How to treat periodontal disease
- Mouthwash for gingivitis — what does the evidence say really works?
- Dental calculus — how to recognise it and remove it effectively
Content and liability disclaimer
This article is informational and educational in nature and does not constitute medical advice, a diagnosis or a therapeutic recommendation — it does not replace a consultation with a specialist. If you are experiencing symptoms, have doubts or are facing a decision about treatment, consult a dentist. The methods described and the data cited are general in nature. The results of scientific studies relate to populations, not to an individual patient. The course and outcome of therapy depend on the individual clinical situation and may vary between patients. No information contained in this article constitutes a guarantee of result. The content has been prepared with due care, based on publicly available medical knowledge and the scientific publications indicated in the Sources section. We do not advise taking or refraining from any health-related action solely on the basis of the content of this article, without prior consultation with a doctor.
Sources
Source 1
Links https://doi.org/10.1016/j.identj.2026.109436 │ https://pubmed.ncbi.nlm.nih.gov/41678945/
Description Shang X, Chen X, Lv C, Wang Z, Chen B, Shao J, et al. „Clinical Practice Guidelines on the Diagnosis and Treatment of Halitosis.” International Dental Journal. 2026;76(2):109436.
Source 2
Links https://doi.org/10.1016/j.identj.2025.109332 │ https://pubmed.ncbi.nlm.nih.gov/41519682/
Description Iranitalab M, Ouanounou A. „Drug-Related Halitosis: A Narrative Review.” International Dental Journal. 2026;76(2):109332.
Source 3
Links https://doi.org/10.1007/s00784-024-05732-0 │ https://pubmed.ncbi.nlm.nih.gov/38801476/
Description Wang N, Li C, Zhang J, Wang L, Yang J. „The association between halitosis and periodontitis: a systematic review and meta-analysis.” Clinical Oral Investigations. 2024;28(6):341.
Source 4
Links https://doi.org/10.1111/jre.12931 │ https://pubmed.ncbi.nlm.nih.gov/34486723/
Description Stephen AS, Dhadwal N, Nagala V, Gonzales-Marin C, Gillam DG, Bradshaw DJ, Burnett GR, Allaker RP. „Interdental and subgingival microbiota may affect the tongue microbial ecology and oral malodour in health, gingivitis and periodontitis.” Journal of Periodontal Research. 2021;56(6):1174-1184.
Source 5
Links https://doi.org/10.1007/s10266-024-01004-1 │ https://pubmed.ncbi.nlm.nih.gov/39279011/
Description Silva MLV, Viana KSS, de Arruda JAA, de Miranda RD, Soares MCF, Calado HDR, et al. „Volatile sulfur compounds, biofilm, and salivary parameters in patients with periodontal disease: a cross-sectional study.” Odontology. 2025;113(2):809-817.
Source 6
Links https://doi.org/10.1590/1678-7757-2022-0412 │ https://pubmed.ncbi.nlm.nih.gov/37132667/
Description Rodrigues NCP, Abrão Neto A, Nadanovsky P. „Accuracy of two methods to detect the presence of halitosis: the volatile sulfur compounds concentration in the mouth air and the information from a close person.” Journal of Applied Oral Science. 2023;31:e20220412.
Source 7
Links https://doi.org/10.1016/j.identj.2023.08.014 │ https://pubmed.ncbi.nlm.nih.gov/37867064/
Description McGrath C, Clarkson J, Glenny AM, Walsh LJ, Hua F. „Effectiveness of Mouthwashes in Managing Oral Diseases and Conditions: Do They Have a Role?” International Dental Journal. 2023;73(Suppl 2):S69-S73.
Source 8
Links https://doi.org/10.1111/adj.12860 │ https://pubmed.ncbi.nlm.nih.gov/34028827/
Description Aliyev B, Pasaoglu O, Pasaoglu H, Gungor K, Guner E, Celik B, Tuter G. „Salivary β-galactosidase, halitosis parameters in periodontal health and disease, and their changes after periodontal treatment.” Australian Dental Journal. 2021;66(4):377-384.
Source 9
Links https://doi.org/10.1186/s12903-025-05702-2 │ https://pubmed.ncbi.nlm.nih.gov/40022178/
Description Tastan Eroglu Z, Kalender ME, Ucan Yarkac F, Babayigit O, Ozkan Sen D. „Impact of non-surgical periodontal therapy on self-perceived halitosis, and the senses of smell and taste: a prospective clinical study.” BMC Oral Health. 2025;25(1):321.
Source 10
Links https://doi.org/10.1111/jcpe.13290 │ https://pubmed.ncbi.nlm.nih.gov/32383274/
Description Sanz M, Herrera D, Kebschull M, Chapple I, Jepsen S, Berglundh T, Sculean A, Tonetti MS; EFP Workshop Participants and Methodological Consultants. „Treatment of stage I-III periodontitis-The EFP S3 level clinical practice guideline.” Journal of Clinical Periodontology. 2020;47(Suppl 22):4-60.