Intended for healthcare professionals

Clinical Review

Oral malodour (halitosis)

BMJ 2006; 333 doi: (Published 21 September 2006) Cite this as: BMJ 2006;333:632
  1. S R Porter (, professor of oral medicine1,
  2. C Scully, dean and director of studies and research1
  1. 1 Oral Medicine Unit, UCL Eastman Dental Institute, 256 Gray's Inn Road, London WC1X 8LD
  1. Correspondence to: S R Porter
  • Accepted 21 August 2006


Oral malodour (halitosis) is common; most people have some element of transient unpleasant oral odour at some time.1 w1 In the developed world, 8-50% of people perceive that they have persistent recurrent episodes of oral malodour. This article provides a succinct review of oral malodour relevant to medical practitioners.

Who gets halitosis?

Oral malodour is common and can affect people of all ages. When severe or longstanding, it may decrease self confidence and social interactions.w2

What is the most likely cause of halitosis?

Oral malodour on awakening is common and generally not regarded as halitosis. Longstanding oral malodour is usually caused by oral, or sometimes nasopharyngeal, disease (box 1). The most likely cause of oral malodour is the accumulation of food debris and dental bacterial plaque on the teeth and tongue, resulting from poor oral hygiene and resultant gingival (gingivitis) and periodontal (gingivitis/periodontitis) inflammation. Although most types of gingivitis and periodontitis can give rise to malodour, acute necrotising ulcerative gingivitis (Vincent's disease, trench mouth) causes the most notable halitosis. Adult periodontitis, characterised by gradual plaque related loss of periodontal attachment, can cause variable degrees of oral malodour.2 Aggressive periodontitis, typified by rapid loss of periodontal bone and resultant tooth mobility, can cause intense oral malodour.

Lack of oral cleansing because of xerostomia (dryness of the mouth) also has the potential to cause or enhance malodour,w3 and some evidence indicates that wearing dentures may sometimes cause oral malodour, possibly by virtue of increased tongue coat deposits.w4

What other causes of halitosis exist?

Mild transient oral malodour often arises after sleep and is sometimes termed “morning halitosis.” This may be more likely in people with nasal obstruction—for example, due to upper respiratory tract infection—or when people sleep in a hot, dry atmosphere. Transient oral malodour can also arise after someone has eaten volatile foods such as garlic, onions, or spices (durian is reputed to …

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