Professional Reference articles are designed for health professionals to use. They are written by UK doctors and based on research evidence, UK and European Guidelines. You may find the Halitosis (Bad Breath) article more useful, or one of our other health articles.
Treatment of almost all medical conditions has been affected by the COVID-19 pandemic. NICE has issued rapid update guidelines in relation to many of these. This guidance is changing frequently. Please visit https://www.nice.org.uk/covid-19 to see if there is temporary guidance issued by NICE in relation to the management of this condition, which may vary from the information given below.
Synonym: bad breath, oral malodour
What is halitosis?
Halitosis describes an unpleasant or offensive odour in the breath or malodour beyond a socially acceptable level regardless of the underlying cause.
The causes of halitosis include:
Usually transient and normal (eg, following a night's sleep or fasting, but may also be lifestyle-related, eg, smoking or ingesting certain odiferous foods or drinks, eg, garlic, onion, spices, radishes, and alcohol. The halitosis is often transient, but may persist or be recurrent if the causative food or drink is consumed regularly.
- Intra-oral halitosis: the odour originates from a problem within the mouth (80–85% of cases of persistent, objective halitosis). Increased microbial activity of bacterial reservoirs within the mouth (may be linked to poor oral hygiene), such as:
- Tongue coating.
- Gingivitis and periodontitis.
- Dry mouth (xerostomia), which may be caused by smoking, alcohol, drugs, radiotherapy, chemotherapy, and Sjögren's syndrome.
- Poor denture hygiene, including not taking dentures out at night, and inadequate teeth cleaning.
- Other oral and dental diseases, eg, dry socket (alveolar osteitis), dental abscess, oral infections (eg, oral candidiasis or herpetic gingivostomatitis), oroantral fistula, and oral cancer.
- Extra-oral halitosis: the odour originates from a non-oral disease (5–10% of cases):
- Nasal, paranasal, and laryngeal conditions, eg, infection (oral candidiasis, sinusitis, tonsillitis, or nasopharyngeal abscess), tonsilloliths (mineralised debris in the tonsillar crypts), nasal foreign bodies, nasal obstruction/congestion leading to mouth breathing, postnasal drip, and malignancy.
- Respiratory conditions, eg, upper respiratory tract infection, lower respiratory infection or abscess, bronchiectasis, and lung cancer.
- Gastrointestinal tract conditions, eg, gastro-oesophageal reflux disease, hiatus hernia, Helicobacter pylori infection, duodenal obstruction, oesophageal diverticulum, and gastrointestinal cancer.
- Systemic diseases, eg, cirrhosis and hepatic failure, end-stage renal failure (uraemia), diabetic ketoacidosis.
- Drugs, including bisphosphonates, disulfiram, lithium, melatonin, metronidazole, nicotine lozenges, mycophenolate sodium, amyl nitrites, nitrates, phenothiazine, amphetamines, and some cytotoxic drugs.
Psychogenic or subjective:
- Pseudo-halitosis: the person eventually accepts that they do not have halitosis with reassurance, explanation, and self-care advice.
- Halitophobia: the person has a persistent fear of having halitosis despite reassurance, explanation, and treatment. They may become fixated with teeth and tongue cleaning, and may change their behaviour (eg, covering their mouth when talking and avoiding people), to try and minimise perceived symptoms, and may misinterpret other people's behaviour (eg, opening windows, sniffing, touching the nose) as evidence of their halitosis.
How common is halitosis? (Epidemiology)
There are no reliable estimates of prevalence. One large systematic review and meta-regression analysis found an estimated prevalence of halitosis to be 31.8%, but there was high heterogeneity between studies.
Most studies support the proposition that halitosis is an underestimated oral health problem in the general population. This is largely based on the fact that many sufferers are either not aware of it or too embarrassed about their condition to report it or seek help.
Consider a possible cause for halitosis as listed above.
Confirm that objective halitosis is present by assessing the person's breath:
- The person should not wear fragrances prior to the assessment, or consume odiferous foods or drinks for 48 hours (and should ideally only drink water on the morning of the assessment), and should not smoke for 12 hours.
- Ask the person to breathe out of their mouth (pinching the nose), and then to breathe out of their nose (with the mouth closed), and smell the person's exhaled breath. Halitosis is likely to be:
- Oral or pharyngeal in origin if malodour is detected from the mouth but not from the nose.
- Nasal or sinus in origin if malodour is detected from the nose but not from the mouth.
- Systemic in origin if malodour from the nose and mouth are of equal intensity (rare).
- Consider repeating the assessment on two or three occasions if no halitosis is detected on the initial examination.
Consider a diagnosis of pseudo-halitosis or halitophobia if halitosis is not detected on any occasion.
Assess the person's oral health. Examine the teeth, tongue, and oral cavity to assess for oral causes of halitosis, such as malaligned teeth, dental caries, periodontal disease, tongue coating, and plaque. Tongue coating may be a cause of halitosis even in people with otherwise good dental hygiene and oral health.
Provide reassurance, advice and treatment depending on the likely underlying cause.
- If there is any uncertainty about the possibility of oral disease (such as gingivitis or periodontitis), advise an appointment with a dentist for a full oral examination, especially if the person does not attend dental appointments regularly.
- Encourage lifestyle changes if appropriate, such as:
- Avoiding or limiting causative foods or drinks.
- Drinking sufficient fluids; eating breakfast, chewing or eating acidic foods.
- Stopping smoking.
- Limiting excess alcohol intake.
- Advise on the importance of general oral hygiene measures, including cleaning the teeth, interdental spaces, and tongue. With regard to cleaning the tongue:
- Advise a proprietary tongue cleaner/scraper rather than a toothbrush.
- Use a gentle scraping action, and avoid excessive scraping as this can cause damage and bleeding to the tongue.
- Cleaning should be repeated until no more coating material can be removed.
- Care should be taken to avoid triggering the gag reflex.
- Advise to limit the frequency and amount of sugary food and drinks.
- Advise on the importance of attending regular dental appointments to ensure maintenance of good oral hygiene.
- Give advice regarding mouthwashes if halitosis persists.
A Cochrane review compared different types of interventions, including mechanical debridement, chewing gums, systemic deodorising agents, topical agents, toothpastes, mouthrinse/mouthwash, tablets, and combination methods. The review found low/very low-certainty evidence to support the effectiveness of interventions for managing halitosis and was unable to provide any conclusions regarding the superiority of any intervention or concentration.
- Negative psychosocial impact and reduced quality of life including effect on work and personal relationships.
- Reduced self-confidence, social stigma and embarrassment, and social isolation.
- Anxiety and depression.
- Behavioural changes: people with halitophobia may become fixated with teeth and tongue cleaning, and may change their behaviour to try and minimise perceived symptoms.
Further reading and references
Tungare S, Zafar N, Paranjpe AG; Halitosis. StatPearls, Aug 2022.
Gingivitis and periodonitis; NICE CKS, December 2021
Poniewierka E, Pleskacz M, Luc-Pleskacz N, et al; Halitosis as a symptom of gastroenterological diseases. Prz Gastroenterol. 202217(1):17-20. doi: 10.5114/pg.2022.114593. Epub 2022 Mar 18.
Halitosis; NICE CKS, September 2019 (UK access only)
Bollen CM, Beikler T; Halitosis: the multidisciplinary approach. Int J Oral Sci. 2012 Jun4(2):55-63.
Silva MF, Leite FRM, Ferreira LB, et al; Estimated prevalence of halitosis: a systematic review and meta-regression analysis. Clin Oral Investig. 2018 Jan22(1):47-55. doi: 10.1007/s00784-017-2164-5. Epub 2017 Jul 4.
Wu J, Cannon RD, Ji P, et al; Halitosis: prevalence, risk factors, sources, measurement and treatment - a review of the literature. Aust Dent J. 2020 Mar65(1):4-11. doi: 10.1111/adj.12725. Epub 2019 Nov 15.
Scully C; Halitosis. BMJ Clin Evid. 2014 Sep 182014:1305.
Kumbargere Nagraj S, Eachempati P, Uma E, et al; Interventions for managing halitosis. Cochrane Database Syst Rev. 2019 Dec 1112(12):CD012213. doi: 10.1002/14651858.CD012213.pub2.