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Halitosis - the evidence-base for treatment

Latest in the series offering evidence-based advice not covered by official guidelines.

Latest in the series offering evidence-based advice not covered by official guidelines.

Basic rules

• Neglecting oral hygiene is the most important reason for bad breath. In at least 80% of the cases the cause is found in the mouth. The smell is mainly caused by volatile sulphur compounds (VSC) produced by bacteria.

• The sense of smell adapts quickly even to a strong smell, and the patient is often unaware of the problem.

• Transient oral malodour on awakening is a natural phenomenon. Mouth breathing aggravates the malodour.

• Halitosis may cause significant social impairment, fear of social situations and social withdrawal.

• If no specific treatable cause is found, management of halitosis is based on careful oral hygiene, stimulation of salivary flow and use of refreshing mouthwashes or gargles.

Causes of bad breath

• Poor oral hygiene, dental caries1, periodontal diseases2, and difficulty in cleaning prostheses.

• Reduced salivation and drying of the mouth

  • Sjögren's syndrome
  • Radiotherapy and post-operative conditions
  • Anticholinergic drugs

• Bad-smelling nutrients, drugs, and stimulants and their degradation products Garlic

  • Tobacco
  • Alcohol
  • Isosorbide nitrate
  • Disulfiram

• Infection and putrefaction

  • Salivary glands, tongue, ulcers and lesions of the oral mucosa.

• Infection of the tonsils, adenoids or lingual tonsil

• Tonsillary plugs: whitish or yellowish foul-smelling grainy mass is accumulated in the tonsillary crypts and is shed by pressure on the crypt.

• Retropharyngeal or nasopharyngeal accumulation of mucus and pus, adenoids (cause mouth breathing, particularly in children), maxillary sinusitis

• Nasal tumours, foreign bodies, other causes increasing mouth breathing

• Atrophic rhinitis and ozaena

• Oesophageal diverticles, achalasia, reflux disease

• Bronchitis, bronchiectasis, pulmonary empyema

• Some systemic diseases

  • Diabetes
  • Renal and hepatic failure

• If no-one else has reported on the patient having oral malodour, the patient may suffer from a disturbance of the sense of smell or from olfactory hallucinations.


• Treatment is aetiology-specific. Severe tonsil-associated malodour problem may warrant tonsillectomy.

• When no specific treatable cause is found, the management consists of attempts to increase salivary secretion, to decrease the amount of bacteria in the mouth and to mask the odour

• Good oral hygiene, tongue brushing or scraping (level of evidence = C)

• Stimulation of salivation by the use of chewing gum or lozenges; artificial saliva

• Non-alcoholic antimicrobial mouthwashes and gargles (level of evidence = C)

  • Mouthwashes and toothpastes containing e.g. chlorhexidine, cetylpyridinium or triclosan temporarily decrease the amount of odour-producing bacteria. Disadvantages of chlorhexidine include unpleasant taste and staining of teeth.

• Lozenges, mouthwashes and sprays intended for masking the odour have a momentary effect only.

This synopsis is taken from EBM Guidelines, a collection of treatment and diagnosis guidelines supported by evidence summaries.

Copyright Duodecim Medical Publications Ltd.

Distributed by Wiley-Blackwell. For more information, email: or visit


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