How common is bad breath, and where does it usually come from?
Bad breath (halitosis) is very widespread. According to the Oral Health Foundation, about one in four people has bad breath regularly, and the American Dental Association (ADA) refers to studies suggesting that half of adults are affected at some point in their lives.
According to the Oral Health Foundation, persistent bad breath is usually caused by foul-smelling gases produced by bacteria on the teeth, gums and tongue. A Cochrane review of 2019 (Kumbargere Nagraj and colleagues) notes that bad breath is widely considered to originate in the mouth; in a study it cites of 2,000 patients at a Belgian bad-breath clinic, 76 percent had a probable cause in the mouth. According to the same review, 3 to 10 percent of cases are traced to the ear, nose and throat region.
Which problems in the mouth lead to bad breath?
What the causes in the mouth have in common is that bacteria collect where cleaning is difficult:
- Tongue coating: according to the Cochrane review, the odour usually comes from excess bacteria and food debris, above all on the back of the tongue. Mayo Clinic notes that the back of the tongue is the most frequent source.
- Gum inflammation and tartar: see the next section.
- Decay and infections: the NHS counts gum disease, decayed teeth and infections among the causes; Mayo Clinic adds healing wounds after extractions and mouth ulcers.
- Dry mouth: according to the ADA, saliva cleanses the mouth; dryness can be caused by medicines, salivary gland problems or mouth breathing.
- Dental work and appliances: according to Mayo Clinic, poorly cleaned or poorly fitting dentures and braces harbour odour-causing bacteria, and faulty fillings can do the same.
- Smoking: according to Cleveland Clinic, smoking alters the balance of bacteria in the mouth and dries it out; according to the ADA, smokers often do not notice their own breath odour.
How do gum inflammation and tartar contribute?
Gum disease is one of the most important causes in the mouth. If plaque is not removed regularly, the gum becomes inflamed (gingivitis). According to Mayo Clinic, this can develop into periodontitis, which spreads to the tissues holding the teeth. The NHS names bad breath and a bad taste among the consequences of gum disease; according to the ADA, persistent bad breath or a constant bad taste can be a warning sign of advanced gum disease. The American Academy of Periodontology and Mayo Clinic also count persistent bad breath among the signs of periodontitis, together with bleeding gums, recession and loose teeth.
Plaque hardens over time into tartar, which can no longer be brushed away. According to Cleveland Clinic, plaque-related odour usually responds to a cleaning at the dental practice and better care at home. If the odour is joined by bleeding gums, swelling, receding gums or loose teeth, the gums should be examined; see our guides on bleeding gums, receding gums and gum disease treatment.
Do mouthwash, chewing gum and mints help?
Rinses, mints and chewing gum mask the odour briefly but do not remove the cause. According to the ADA, over-the-counter rinses can kill bacteria or temporarily mask the odour, but they are only a short-term solution. The Oral Health Foundation writes that a rinse can freshen the breath but does not solve an underlying problem; anyone who constantly needs a rinse should raise it at the practice. According to Mayo Clinic, a dentist may recommend an antibacterial rinse or toothpaste if plaque bacteria are the cause.
Research shows no clearly superior method. The Cochrane review evaluated 44 randomised controlled trials with 1,809 participants that tested tongue cleaning, rinses, toothpastes and chewing gum. Most studies ran for only one to four weeks, and the authors rated the certainty of the evidence as low to very low.
What can you do at home against bad breath?
The NHS recommends these daily steps:
- Brush gently for two minutes at least twice a day with fluoride toothpaste, and do not rinse with water straight afterwards.
- Clean the tongue once a day with a tongue scraper or cleaner.
- Clean between the teeth at least once a day with interdental brushes or floss.
- Keep dentures clean and take them out at night.
- Use sugar-free mints or sugar-free chewing gum after strong-smelling food.
- Do not smoke; limit alcohol and sugary food and drink.
- Do not brush so hard that the gums or tongue bleed.
Cleveland Clinic also advises drinking plenty of water against dry mouth and chewing sugar-free gum to stimulate saliva; Mayo Clinic recommends the same and limiting caffeine and alcohol.
Which causes lie outside the mouth?
If the teeth and mouth are healthy and the odour remains, the source may lie elsewhere. The sources name above all:
| Area | Examples |
|---|---|
| Nose, throat, sinuses | Tonsillitis, tonsil stones, sinusitis, post-nasal drip (NHS, Mayo Clinic, Oral Health Foundation) |
| Lungs and airways | Infections of the throat, chest or lungs; chronic airway disease (Cleveland Clinic, Oral Health Foundation) |
| Digestion | Reflux disease, in which stomach acid rises (NHS, Cleveland Clinic, ADA) |
| Metabolism | Diabetes; according to Cleveland Clinic the breath smells fruity in diabetic ketoacidosis |
| Liver and kidneys | Chronic disease (ADA, Cleveland Clinic, Oral Health Foundation) |
| Medicines | Drugs that dry the mouth or whose breakdown products are released on the breath (Mayo Clinic, Cleveland Clinic) |
| Diet | Prolonged fasting and very strict diets (NHS) |
The path is clear in the sources: according to the ADA, you should seek medical advice if your dentist considers your mouth healthy and the odour remains. If you have diabetes and notice a fruity smell on your breath, speak to your doctor without delay.
How do I know if I have bad breath, and when should I see a dentist?
Judging your own breath is difficult. According to Mayo Clinic, some people worry about their breath although they have little or no odour, while others do not notice theirs; dentists therefore ask whether other people have commented on it. The Oral Health Foundation names a strange taste as a possible sign and suggests two tests: lick the inside of your wrist and smell it after a few seconds, or ask someone you trust to be honest.
According to the NHS, you should see a dentist if:
- the odour remains despite several weeks of careful care
- the gums are sore, bleeding or swollen
- you have toothache or an adult tooth is loose
- there are problems with a denture
According to Mayo Clinic, the dentist smells the breath from the mouth and nose and rates the odour, and may scrape the back of the tongue; instruments that detect the responsible chemicals exist but are not always available.
What does this mean for patients travelling from abroad?
Bad breath alone is no reason to travel; the assessment belongs with a dentist near you and, if needed, your doctor. The topic becomes relevant for us when you are planning treatment anyway or wear dental work from our clinic: at the examination at our clinic in Serdivan, the teeth, gums, tongue, fillings, crowns and any existing dentures are assessed, and decay, tartar and signs of gum disease are looked for, with X-rays where needed. If tartar or gum inflammation is behind it, treatment follows from that; endodontics (root canal treatment) and prosthodontics are among our fields, so an infected tooth or a poorly fitting denture can be discussed at the same appointment. If no cause is found in the mouth, we recommend, like the sources, the route to your own doctor.
If you wear implants, crowns or a denture from our clinic, daily cleaning of the margins and the spaces between the teeth helps most; see our guides on caring for teeth on implants and caring for zirconia crowns, and our page on dentures. If the odour remains, or the gum around an implant bleeds, have it examined by a dentist near you and send us a photo on WhatsApp at +90 532 363 49 54; during opening hours we reply to messages in English within 15 minutes. More on our page on aftercare and follow-up.