View source for Bad breath

{{Short description|Presence of unpleasant odors in exhaled breath}}
{{Use Oxford spelling|date=July 2020}}
{{Redirect|Halitosis|the genus of molluscs|Haliotis}}
{{Infobox medical condition (new)
| name            = Bad breath
| synonyms        = Halitosis, fetor oris, oral malodour, putrid breath 
| image           = Depiction of a person who has Halitosis (or bad breath).png
| caption         = 
| field           = [[Gastroenterology]], [[otorhinolaryngology]], [[dentistry]]
| symptoms        = Unpleasant [[odor|smell]] present on [[breath]]<ref name=Kap2016/>
| complications   = [[Anxiety]], [[Mood disorder|depression]], [[obsessive compulsive disorder]]<ref name=Kap2016/>
| onset           = 
| duration        = 
| types           = Genuine, non-genuine<ref name=Har2013/>
| causes          = Usually from inside the mouth<ref name=Kap2016/>
| risks           = 
| diagnosis       = 
| differential    = 
| prevention      = 
| treatment       = Depends on cause, [[tongue cleaning]], [[mouthwash]], [[flossing]]<ref name=Kap2016/>
| medication      = Mouthwash containing [[chlorhexidine]] or [[cetylpyridinium chloride]]<ref name=Kap2016/>
| prognosis       = 
| frequency       = ~30% of people<ref name=Kap2016/>
| deaths          = 
}}

'''Bad breath''', also known as '''halitosis''', is a [[medical symptom|symptom]] in which a noticeably unpleasant [[breath]] [[odour]] is present.<ref name=Kap2016/> It can result in [[anxiety]] among those affected.<ref name=Kap2016/> It is also associated with [[Mood disorder|depression]] and symptoms of [[obsessive compulsive disorder]].<ref name=Kap2016>{{cite journal|last1=Kapoor|first1=U|last2=Sharma|first2=G|last3=Juneja|first3=M|last4=Nagpal|first4=A|title=Halitosis: Current concepts on etiology, diagnosis and management.|journal=European Journal of Dentistry|date=2016|volume=10|issue=2|pages=292–300|pmid=27095913|doi=10.4103/1305-7456.178294|pmc=4813452|doi-access=free}}</ref>

The concerns of bad breath may be divided into genuine and non-genuine cases.<ref name=Har2013>{{cite journal|last1=Harvey-Woodworth|first1=CN|title=Dimethylsulphidemia: the significance of dimethyl sulphide in extra-oral, blood borne halitosis.|journal=British Dental Journal|date=April 2013|volume=214|issue=7|pages=E20|doi=10.1038/sj.bdj.2013.329|pmid=23579164|doi-access=free}}</ref> Of those who have genuine bad breath, about 85% of cases come from inside the mouth.<ref name=Kap2016/> The remaining cases are believed to be due to disorders in the [[nasal cavity|nose]], [[Paranasal sinuses|sinuses]], [[throat]], [[lung]]s, [[esophagus]], or [[stomach]].<ref name=Loe2002/> Rarely, bad breath can be due to an underlying medical condition such as [[liver failure]] or [[ketoacidosis]].<ref name=Har2013/> Non-genuine cases occur when someone complains of having bad breath, but other people cannot detect it.<ref name=Har2013/> This is estimated to make up between 5% and 72% of cases.<ref name=Har2013/>

The treatment depends on the underlying cause.<ref name=Kap2016/> Initial efforts may include [[tongue cleaning]], [[mouthwash]], and [[flossing]].<ref name=Kap2016/> Tentative evidence supports the use of mouthwash containing [[chlorhexidine]] or [[cetylpyridinium chloride]].<ref name=Kap2016/> While there is tentative evidence of benefit from the use of a tongue cleaner, it is insufficient to draw clear conclusions.<ref name=Van2010>{{Cite journal|last1=Van der Sleen|first1=Mi|last2=Slot|first2=De|last3=Van Trijffel|first3=E|last4=Winkel|first4=Eg|last5=Van der Weijden|first5=Ga|date=2010-11-01|title=Effectiveness of mechanical tongue cleaning on breath odour and tongue coating: a systematic review|journal=International Journal of Dental Hygiene|language=en|volume=8|issue=4|pages=258–268|doi=10.1111/j.1601-5037.2010.00479.x|issn=1601-5037|pmid=20961381}}</ref> Treating underlying disease such as [[gum disease]], [[tooth decay]], [[tonsil stones]], or [[gastroesophageal reflux disease]] may help.<ref name=Kap2016/> [[Counselling]] may be useful for those who falsely believe that they have bad breath.<ref name=Kap2016/>

The estimated rates of bad breath vary from 6% to 50% of the population.<ref name=Kap2016/> Concern about bad breath is the third most common reason people seek [[dentistry|dental care]], after tooth decay and gum disease.<ref name=Har2013/><ref name=Loe2002>{{cite journal|last1=Loesche|first1=WJ|last2=Kazor|first2=C|title=Microbiology and treatment of halitosis.|journal=Periodontology 2000|date=2002|volume=28|pages=256–79|pmid=12013345|doi=10.1034/j.1600-0757.2002.280111.x}}</ref> It is believed to become more common as people age.<ref name=Kap2016/> Bad breath is viewed as a social [[taboo]] and those affected may be [[stigmatized]].<ref name=Kap2016/><ref name=Har2013/> People in the United States spend more than $1 billion per year on mouthwash to treat it.<ref name=Loe2002/>
{{TOC limit|3}}

==Signs and symptoms==
Bad breath is when a noticeably unpleasant [[odour]] is believed to be present on the [[breath]].<!-- <ref name=Kap2016/> --> It can result in [[anxiety]] among those affected.<!-- <ref name=Kap2016/> --> It is also associated with [[Mood disorder|depression]] and symptoms of [[obsessive compulsive disorder]].<ref name=Kap2016/>

== Causes ==

=== Mouth ===
In about 90% of genuine halitosis cases, the origin of the odour is in the mouth itself.<ref name="rosenberg0">{{cite journal|pmid=11905111|year=2002|last1=Rosenberg|first1=M|title=The science of bad breath|volume=286|issue=4|pages=72–9|journal=Scientific American|doi=10.1038/scientificamerican0402-72|bibcode=2002SciAm.286d..72R}}</ref> This is known as intra-oral halitosis, oral malodour or oral halitosis.

The most common causes are odour-producing [[biofilm]] on the [[posterior (anatomy)|back]] of the tongue or other areas of the mouth due to poor oral hygiene. This biofilm results in the production of high levels of foul odours. The odours are produced mainly due to the breakdown of [[protein]]s into individual [[amino acid]]s, followed by the further breakdown of certain amino acids to produce detectable foul [[gas]]es. Volatile sulfur compounds are associated with oral malodour levels, and usually decrease following successful treatment.<ref name="Rosenberg 1996">{{cite journal|pmid=8655868|year=1996|last1=Rosenberg|first1=M|title=Clinical assessment of bad breath: Current concepts|volume=127|issue=4|pages=475–82|journal=Journal of the American Dental Association|doi=10.14219/jada.archive.1996.0239}}</ref> Other parts of the mouth may also contribute to the overall odour, but are not as common as the back of the tongue. These locations are, in order of descending prevalence, inter-dental and sub-gingival niches, faulty [[dentistry|dental]] work, food-impaction areas in between the teeth, [[abscess]]es, and unclean [[dentures]].<ref name="Scully 2003">Scully C, Rosenberg M. Halitosis. ''Dent Update''. 2003 May;3</ref> Oral based lesions caused by viral infections like [[herpes simplex]] and [[Human papillomavirus infection|HPV]] may also contribute to bad breath.

The intensity of bad breath may differ during the day, due to eating certain foods (such as [[garlic]], [[onion]]s, [[meat]], [[Fish as food|fish]], and [[cheese]]), [[tobacco smoking|smoking]],<ref name="Zalewska 2012">{{cite journal|last=Zalewska|first=A|author2=Zatoński, M |author3=Jabłonka-Strom, A |author4=Paradowska, A |author5=Kawala, B |author6= Litwin, A |title=Halitosis--a common medical and social problem. A review on pathology, diagnosis, and treatment.|journal=Acta Gastro-enterologica Belgica|date=September 2012|volume=75|issue=3|pages=300–9|pmid=23082699}}</ref> and [[alcohol consumption and health|alcohol consumption]]. Since the mouth is exposed to less oxygen{{medical citation needed|date=July 2013}} and is inactive during the night, the odour is usually worse upon awakening ("'''morning breath'''"). Bad breath may be transient, often disappearing following eating, drinking, [[tooth brushing]], [[flossing]], or rinsing with specialized [[mouthwash]]. Bad breath may also be persistent (chronic bad breath), which affects some 25% of the population in varying degrees.<ref>{{cite journal|pmid=9086681|year=1997|last1=Bosy|first1=A|title=Oral malodor: Philosophical and practical aspects|volume=63|issue=3|pages=196–201|journal=Journal (Canadian Dental Association)}}</ref>

==== Tongue ====
[[File:Lgive lashon (cropped).JPG|thumb|Normal appearance of the tongue, showing a degree of visible white coating and normal irregular surface on the posterior dorsum]]
The most common location for mouth-related halitosis is the [[tongue]].<ref name=nachnani0>{{cite journal|pmid=21462620|year=2011|last1=Nachnani|first1=S|title=Oral malodor: Causes, assessment, and treatment|volume=32|issue=1|pages=22–4, 26–8, 30–1; quiz 32, 34|journal=Compendium of Continuing Education in Dentistry}}</ref> Tongue bacteria produce malodourous compounds and fatty acids, and account for 80 to 90% of all cases of mouth-related bad breath.<ref>{{cite news | url=https://www.reuters.com/article/idUSTON77980320080407 | work=Reuters | title=Scientists find bug responsible for bad breath | date=April 7, 2008 | url-status=live | archive-url=https://web.archive.org/web/20100529065227/http://www.reuters.com/article/idUSTON77980320080407 | archive-date=May 29, 2010 }}</ref> Large quantities of naturally occurring bacteria are often found on the posterior [[Dorsum (biology)|dorsum]] of the tongue, where they are relatively undisturbed by normal activity. This part of the tongue is relatively dry and poorly cleansed, and the convoluted microbial structure of the tongue dorsum provides an ideal [[habitat]] for [[anaerobic bacteria]], which flourish under a continually-forming tongue coating of [[food]] debris, [[epithelium|dead epithelial cells]], [[postnasal drip]] and overlying bacteria, living and dead. When left on the tongue, the [[anaerobic respiration]] of such bacteria can yield either the [[putrefaction|putrescent]] smell of [[indole]], [[skatole]], [[polyamine]]s, or the "rotten egg" smell of [[organosulfur compounds|volatile sulfur compounds]] (VSCs) such as [[hydrogen sulfide]], [[methyl mercaptan]], [[allyl methyl sulfide]], and [[dimethyl sulfide]]. The presence of halitosis-producing bacteria on the back of the tongue is not to be confused with tongue coating. Bacteria are invisible to the naked eye, and degrees of white tongue coating are present in most people with and without halitosis. A visible white tongue coating does not always equal the back of the tongue as an origin of halitosis; however, a "[[Tongue disease|white tongue]]" is thought to be a sign of halitosis. In [[oral medicine]], generally, a white tongue is considered a sign of several medical conditions. Patients with periodontal disease were shown to have a sixfold prevalence of tongue coating compared with normal subjects. Halitosis patients were also shown to have significantly higher bacterial loads in this region compared to individuals without halitosis.

==== Gums ====
Gingival crevices are the small grooves between teeth and gums, and they are present in health, although they may become inflamed when [[gingivitis]] is present. The difference between a gingival crevice and [[periodontal pocket]] is that the former is <3mm in depth and the latter is >3mm. Periodontal pockets usually accompany [[periodontal disease]] (gum disease). There is some controversy over the role of [[periodontitis|periodontal diseases]] in causing bad breath. However, advanced periodontal disease is a common cause of severe halitosis. People with uncontrolled diabetes are more prone to have multiple gingival and periodontal abscesses. Their gums are evident with large pockets, where pus accumulation occurs. This nidus of infection can be a potential source for bad breath. Removal of the subgingival calculus (i.e., tartar or hard plaque) and friable tissue has been shown to improve mouth odour considerably. This is accomplished by subgingival scaling and root planing and irrigation with an antibiotic mouth rinse. The bacteria that cause gingivitis and periodontal disease (periodontopathogens) are invariably [[Gram negative bacteria|gram negative]] and capable of producing VSC. [[Methyl mercaptan]] is known to be the greatest contributing VSC in halitosis that is caused by periodontal disease and gingivitis. The level of VSC on breath has been shown to positively correlate with the depth of periodontal pocketing, the number of pockets, and whether the pockets bleed when examined with a [[Dental instruments|dental probe]]. Indeed, VSCs may themselves have been shown to contribute to the inflammation and tissue damage that is characteristic of periodontal disease. However, not all patients with periodontal disease have halitosis, and not all patients with halitosis have periodontal disease. Although patients with periodontal disease are more likely to develop halitosis than the general population, the halitosis symptom was shown to be more strongly associated with the degree of tongue coating than with the severity of periodontal disease. Another possible symptom of periodontal disease is a bad taste, which does not necessarily accompany a malodour that is detectable by others.

==== Other causes ====
Other less common reported causes from within the mouth include:<ref name="Winkel 2008" /><ref name="Carranza 2012" /><ref name="oral and maxillofacial medicine">{{cite book|last=Scully|first=Crispian|title=Oral and maxillofacial medicine: the basis of diagnosis and treatment|year=2008|publisher=Churchill Livingstone|location=Edinburgh|isbn=978-0-443-06818-8|edition=2nd}}</ref>
* Deep carious lesions (dental decay)&nbsp;– which cause localized food impaction and stagnation
* Recent dental extraction sockets&nbsp;– fill with blood clot, and provide an ideal habitat for bacterial proliferation
* Interdental food packing&nbsp;– (food getting pushed down between teeth) – this can be caused by missing teeth, tilted, spaced, or crowded teeth, or poorly contoured approximal [[dental fillings]]. Food debris becomes trapped, undergoes slow bacterial putrefaction and release of malodourous volatiles. Food packing can also cause a localized periodontal reaction, characterized by dental pain that is relieved by cleaning the area of food packing with an interdental brush or floss.
* Acrylic dentures (plastic false teeth)&nbsp;– inadequate denture hygiene practises such as failing to clean and remove the prosthesis each night, may cause a malodour from the plastic itself or from the mouth as microbiota responds to the altered environment. The plastic is actually porous, and the fitting surface is usually irregular, sculpted to fit the edentulous oral anatomy. These factors predispose to bacterial and yeast retention, which is accompanied by a typical smell.
* Oral infections
* [[Oral ulceration]]
* [[Fasting]]
* [[Psychological stress|Stress]] or [[anxiety]]
* [[Menstrual cycle]]&nbsp;– At mid cycle and during [[menstruation]], increased breath VSC were reported in women.
* Smoking&nbsp;– Smoking is linked with periodontal disease, which is the second most common cause of oral malodour. Smoking also has many other negative effects on the mouth, from increased rates of dental decay to [[premalignant lesions]] and even [[oral cancer]].
* Alcohol
* Volatile foods – e.g. onion, [[garlic breath|garlic]], durian, cabbage, cauliflower and radish. Volatile foodstuffs may leave malodourous residues in the mouth, which are subject to bacterial putrefaction and VSC release. However, volatile foodstuffs may also cause halitosis via the blood-borne halitosis mechanism.
* Medication&nbsp;– often medications can cause [[xerostomia]] (dry mouth), which results in increased microbial growth in the mouth.

=== Nose and sinuses ===
In this occurrence, the air exiting the [[nostril]]s has a pungent odour that differs from the oral odour. Nasal odour may be due to [[sinus infection]]s or [[foreign bodies]].<ref name="Rosenberg 1996"/><ref name="Scully 2003" />

Halitosis is often stated to be a symptom of [[chronic rhinosinusitis]]; however, gold standard breath analysis techniques have not been applied. Theoretically, there are several possible mechanisms of both objective and subjective halitosis that may be involved.<ref name=Ferguson2014>{{cite journal|last1=Ferguson|first1=M|title=Rhinosinusitis in oral medicine and dentistry.|journal=Australian Dental Journal|date=May 23, 2014|doi=10.1111/adj.12193|pmid=24861778|volume=59|issue=3|pages=289–295|doi-access=free}}</ref>

=== Tonsils ===
There is disagreement as to the proportion of halitosis cases that are caused by conditions of the tonsils.<ref name=Ferguson2014b>{{cite journal|last1=Ferguson|first1=M|last2=Aydin|first2=M|last3=Mickel|first3=J|title=Halitosis and the Tonsils: A Review of Management.|journal=Otolaryngology–Head and Neck Surgery|date=Aug 5, 2014|doi=10.1177/0194599814544881|pmid=25096359|volume=151|issue=4|pages=567–74|s2cid=39801742}}</ref> Some claim that the tonsils are the most significant cause of halitosis after the mouth.<ref name=Ferguson2014b /> According to one report, approximately 3% of halitosis cases were related to the tonsils.<ref name=Ferguson2014b /> Conditions of the tonsils that may be associated with halitosis include chronic caseous [[tonsillitis]] (cheese-like material can be exuded from the [[Tonsil crypts|tonsillar crypt orifi]]), [[tonsillolith]]iasis (tonsil stones), and less commonly [[peritonsillar abscess]], [[actinomycosis]], [[fungating lesion|fungating]] [[Malignancy|malignancies]], [[Cartilage|chondroid]] [[choristoma]], and [[inflammatory myofibroblastic tumor]].<ref name=Ferguson2014b />

=== Esophagus ===
The [[lower esophageal sphincter]], which is the valve between the [[stomach]] and the [[esophagus]], may not close properly due to a [[Hiatal Hernia|hiatal hernia]] or [[GERD]], allowing acid to enter the esophagus and gases to escape to the mouth. A [[Zenker's diverticulum]] may also result in halitosis due to food retained in the esophagus.

=== Stomach ===
The [[stomach]] is considered by most researchers as a very uncommon source of bad breath. The esophagus is a closed and collapsed tube, and continuous flow of gas or putrid substances from the [[stomach]] indicates a health problem—such as [[gastroesophageal reflux|reflux]] serious enough to be bringing up stomach contents or a [[fistula]] between the stomach and the esophagus—which will demonstrate more serious manifestations than just foul odour.<ref name=rosenberg0/>

In the case of [[allyl methyl sulfide]] (the byproduct of [[garlic]]'s digestion), odour does not come from the stomach, since it does not get metabolized there.

=== Systemic diseases ===
There are a few systemic (non-oral) medical conditions that may cause foul breath odour, but these are infrequent in the general population. Such conditions are:<ref>{{cite journal|pmid=12090453|year=2002|last1=Tangerman|first1=A|title=Halitosis in medicine: A review|volume=52 Suppl 3|pages=201–6|journal=International Dental Journal|issue=5|doi=10.1002/j.1875-595x.2002.tb00925.x|doi-access=free}}</ref><ref name=tonzetich>{{cite journal|pmid=264535|year=1977|last1=Tonzetich|first1=J|title=Production and origin of oral malodor: A review of mechanisms and methods of analysis|volume=48|issue=1|pages=13–20|journal=Journal of Periodontology|doi=10.1902/jop.1977.48.1.13}}</ref>
# [[Fetor hepaticus]]: an example of a rare type of bad breath caused by chronic [[liver failure]].
# [[Lower respiratory tract infection]]s (bronchial and lung infections).
# [[nephritis|Kidney infections]] and [[kidney failure]].
# [[Carcinoma]].
# [[Trimethylaminuria]] ("fish odour syndrome").
# [[Diabetes mellitus]].
# [[metabolism|Metabolic]] conditions, e.g. resulting in elevated blood [[dimethyl sulfide]].<ref name="Tangerman 2010" />

Individuals affected by the above conditions often show additional, more diagnostically conclusive symptoms than bad breath alone.

=== Delusional halitosis ===
One quarter of the people seeking professional advice on bad breath have an exaggerated concern of having bad breath, known as '''halitophobia''', ''[[delusion]]al halitosis'', or as a manifestation of the [[olfactory reference syndrome]]. They are sure that they have bad breath, although many have not asked anyone for an objective opinion. Bad breath may severely affect the lives of some 0.5–1.0% of the adult population.<ref>{{cite journal|pmid=14699232|year=2003|last1=Lochner|first1=C|last2=Stein|first2=DJ|title=Olfactory reference syndrome: Diagnostic criteria and differential diagnosis|volume=49|issue=4|pages=328–31|journal=Journal of Postgraduate Medicine}}</ref>

== Diagnosis ==
There are 5 examination methods to diagnose halitosis. Self-assessment, others' assessment, organoleptic examination, chemical and enzymatic tests, and halitometry. 
[[File:Diagnostic tests for halitosis.jpg|thumb]]
There are many methods and modified protocols to examine halitosis. Chemical and enzymatic tests determine the presence of the bacterial species, their metabolic products, or enzymes in the mouth, while Halitometers perfectly quantify gases but do not detect halitosis. The examinations by the human nose (self-assessment, feedback, or organoleptic examination by an examiner) directly target to detect halitosis; however, organoleptic examination alone is not
enough for exact diagnosis when the individual has no complaint from halitosis. Informing about the presence, progression, or healing the halitosis primarily depends on two key factors: 1- Self-assessment and 2- Feedback from others. Both are the primary motivators driving individuals with halitosis to seek medical treatment. Other diagnostic tools and methods, however, face significant difficulties.<ref>Aydin M, Bollen CM, Özen ME. Diagnostic Value of Halitosis Examination Methods. Compend Contin Educ Dent. 2016 37(3):174-178</ref> 

=== Self-diagnosis ===
Scientists have long thought that smelling one's own breath odour is often difficult due to [[acclimatization]], although many people with bad breath are able to detect it in others.  Research has suggested that self-evaluation of halitosis is not easy because of preconceived notions of how bad we think it should be. Some people assume that they have bad breath because of bad [[taste]] (metallic, sour, fecal, etc.); however, bad taste is considered a poor indicator.

Patients often self-diagnose by asking a close friend.<ref name=eli1>{{cite journal|pmid=11367966|year=2001|last1=Eli|first1=I|last2=Baht|first2=R|last3=Koriat|first3=H|last4=Rosenberg|first4=M|title=Self-perception of breath odor|volume=132|issue=5|pages=621–6|journal=Journal of the American Dental Association|doi=10.14219/jada.archive.2001.0239}}</ref>

One popular home method to determine the presence of bad breath is to [[licking|lick]] the back of the [[wrist]], let the [[saliva]] dry for a minute or two, and smell the result. This test results in [[overestimate|overestimation]], as concluded from research, and should be avoided.<ref name=rosenberg0/> A better way would be to lightly scrape the posterior back of the tongue with a plastic disposable spoon and to smell the drying residue. Home tests that use a chemical reaction to test for the presence of [[polyamine]]s and sulfur compounds on tongue swabs are now available, but there are few studies showing how well they actually detect the odour. Furthermore, since breath odour changes in intensity throughout the day depending on many factors, multiple testing sessions may be necessary.

=== Testing ===
If bad breath is persistent, and all other medical and dental factors have been ruled out, specialized testing and treatment are required. Hundreds of dental offices and commercial breath clinics now claim to diagnose and treat bad breath.{{Citation needed|date=March 2012}}  They often use several laboratory methods for diagnosis of bad breath:
* [[Halimeter]]: a portable sulfide monitor used to test for levels of sulfur emissions (to be specific, [[hydrogen sulfide]]) in the mouth air. When used properly, this device can be very effective at determining levels of certain VSC-producing bacteria. However, it has drawbacks in clinical applications. For example, other common sulfides (such as [[mercaptan]]) are not recorded as easily and can be misrepresented in test results. Certain foods such as garlic and onions, produce sulfur in the breath for as long as 48 hours and can result in false readings. The Halimeter is also very sensitive to alcohol, so one should avoid drinking alcohol or using alcohol-containing mouthwashes for at least 12 hours prior to being tested. This analog machine loses sensitivity over time and requires periodic recalibration to remain accurate.<ref>{{cite journal|pmid=1474479|year=1992|last1=Rosenberg|first1=M|last2=McCulloch|first2=CA|title=Measurement of oral malodor: Current methods and future prospects|volume=63|issue=9|pages=776–82|journal=Journal of Periodontology|doi=10.1902/jop.1992.63.9.776}}</ref>
* [[Gas chromatography]]: portable machines are being studied.<ref>Andreas Filippi,"Halitosis- a review". Oralprophylaxe & Kinderzahnheilkunde 31 (2009) 4: 173-174.</ref> This technology is designed to digitally measure molecular levels of major VSCs in a sample of mouth air (such as [[hydrogen sulfide]], [[methyl mercaptan]], and [[dimethyl sulfide]]). It is accurate in measuring the sulfur components of the breath and produces visual results in graph form via a computer interface.
* [[BANA test]]: this test is directed to find the salivary levels of an [[enzyme]] indicating the presence of certain halitosis-related bacteria.
* [[beta-galactosidase|β-galactosidase]] test: Salivary levels of this enzyme were found to be correlated with oral malodour.

Although such instrumentation and examinations are widely used in breath clinics, the most important measurement of bad breath (the gold standard) is the actual [[inhalation|sniffing]] and scoring of the level and type of the odour carried out by trained experts ("organoleptic measurements"). The level of odour is usually assessed on a six-point intensity scale.<ref name=Loe2002/><ref name="Rosenberg 1996"/>

=== Classification ===
Several classification schemes have been proposed to define halitosis.<ref name=Aydin2014/>

==== Miyazaki ''et al.'' ====
The Miyazaki ''et al.'' classification was originally described in 1999 in a Japanese scientific publication,<ref name="Miyazaki 1999">{{cite journal|last=Miyazaki|first=H|author2=Arao, M |author3=Okamura, K |author4=Kawaguchi, Y |author5=Toyofuku, A |author6=Hoshi, K |author7= Yaegaki, K. |title=[Tentative classification of halitosis and its treatment needs] (Japanese)|journal=Niigata Dental Journal|year=1999|volume=32|pages=7–11}}</ref>  and has since been adapted to reflect North American society, especially with regards halitophobia.<ref name="Yaegaki 2000">{{cite journal|last=Yaegaki|first=K|author2=Coil, JM|title=Examination, classification, and treatment of halitosis; clinical perspectives.|journal=Journal (Canadian Dental Association)|date=May 2000|volume=66|issue=5|pages=257–61|pmid=10833869|url=http://www.cda-adc.ca/jcda/vol-66/issue-5/257.html|url-status=live|archive-url=https://web.archive.org/web/20130516042210/http://www.cda-adc.ca/jcda/vol-66/issue-5/257.html|archive-date=2013-05-16}}</ref> The classification assumes three primary divisions of the halitosis symptom, namely genuine halitosis, pseudohalitosis, and halitophobia.

* Genuine halitosis
**A. Physiologic halitosis
**B. Pathologic halitosis
***''(i) Oral''
***''(ii) Extra-oral''
* Pseudohalitosis
* Halitophobia

This classification has been criticized for being inflexible, and the pseudohalitosis and halitophbia categories contain psychopathologic connotations.<ref name=Aydin2014/>

==== Tangerman and Winkel ====
The Tangerman and Winkel classification was suggested in Europe in 2002.<ref name="Tangerman 2002">{{cite journal|last=Tangerman|first=A|title=Halitosis in medicine: a review.|journal=International Dental Journal|date=June 2002|volume=52|issue=Suppl 3|pages=201–6|pmid=12090453|doi=10.1002/j.1875-595x.2002.tb00925.x|doi-access=free}}</ref><ref name="Tangerman 2010">{{cite journal|last=Tangerman|first=A|author2=Winkel, EG|title=Extra-oral halitosis: an overview.|journal=Journal of Breath Research|date=March 2010|volume=4|issue=1|article-number=017003|pmid=21386205|doi=10.1088/1752-7155/4/1/017003|s2cid=5342660}}</ref> This classification focuses only on those cases where there is genuine halitosis, and has therefore been criticized for being less clinically useful for dentistry when compared to the Miyazaki ''et al.'' classification.

* Intra-oral halitosis
* Extra-oral halitosis
** A. Blood borne halitosis
*** ''(i) Systemic diseases''
*** ''(ii) Metabolic diseases''
*** ''(iii) Food''
*** ''(iv) Medication''
** B. Non-blood-borne halitosis
*** ''(i) Upper respiratory tract''
*** ''(ii) Lower respiratory tract''

The same authors also suggested that halitosis can be divided according to the character of the odour into 3 groups:<ref name="Tangerman 2010" />

* "Sulfurous or fecal" caused by [[volatile sulfur compound]]s (VSC), most notably [[methyl mercaptan]], [[hydrogen sulfide]] and [[dimethyl sulfide]].
* "Fruity" caused by [[acetone]], present in diabetes.
* "Urine-like or ammoniacal" caused by [[ammonia]], [[dimethyl amine]] and [[trimethylamine]] (TMA), present in [[trimethylaminuria]] and [[uremia]].

==== Aydin and Harvey-Woodworth ====
Based on the strengths and weaknesses of previous attempts at classification, Aydin and Harvey-Woodworth proposed a cause-based classification.<ref name=Aydin2014>{{cite journal|last1=Aydin|first1=M|last2=Harvey-Woodworth|first2=CN|title=Halitosis: a new definition and classification.|journal=British Dental Journal|date=11 July 2014|volume=217|issue=1|pages=E1|doi=10.1038/sj.bdj.2014.552|pmid=25012349|doi-access=free}}</ref>

* Type 0 (physiologic)
* Type 1 (oral)
* Type 2 (airway)
* Type 3 (gastroesophageal)
* Type 4 (blood-borne)
* Type 5 (subjective)

Any halitosis symptom is potentially the sum of these types in any combination, superimposed on the physiologic odour present in all healthy individuals.<ref name=Aydin2014 />

== Management ==
Approaches to improve bad breath may include physical or chemical means to decrease bacteria in the mouth, products to mask the smell, or chemicals to alter the odour creating molecules.<ref name=Kap2016/> Many different interventions have been suggested and trialed such as toothpastes, mouthwashes, lasers, tongue scraping, and mouth rinses.<ref name=":0">{{Cite journal|last1=Kumbargere Nagraj|first1=Sumanth|last2=Eachempati|first2=Prashanti|last3=Uma|first3=Eswara|last4=Singh|first4=Vijendra Pal|last5=Ismail|first5=Noorliza Mastura|last6=Varghese|first6=Eby|date=2019|title=Interventions for managing halitosis|journal=The Cochrane Database of Systematic Reviews|volume=2019|issue=12 |article-number=CD012213|doi=10.1002/14651858.CD012213.pub2|issn=1469-493X|pmc=6905014|pmid=31825092}}</ref> There is no strong evidence to indicate which interventions work and which are more effective.<ref name=":0" /> It is recommended that in those who use [[tobacco products]] stop.<ref name=Kap2016/> Evidence does not support the benefit of dietary changes or [[chewing gum]].<ref name=Kap2016/>

===Mechanical measures===
Brushing the teeth may help.<ref>{{cite web|title=Bad breath - Diagnosis and treatment - Mayo Clinic|url=https://www.mayoclinic.org/diseases-conditions/bad-breath/diagnosis-treatment/drc-20350925|website=www.mayoclinic.org|access-date=19 January 2018|language=en}}</ref> While there is evidence of tentative benefit from [[Tongue cleaner|tongue cleaning]] it is insufficient to draw clear conclusions.<ref name=Van2010 /> [[Flossing]] may be useful.<ref name=Kap2016/>

=== Mouthwashes ===
[[Mouthwash]]es often contain antibacterial agents including [[cetylpyridinium chloride]], [[chlorhexidine]], [[zinc gluconate]], [[zinc chloride]], zinc lactate, [[hydrogen peroxide]], [[chlorine dioxide]], [[amine fluoride]]s, [[stannous fluoride]], [[hinokitiol]],<ref>{{cite journal |last1=Iha |first1=Kosaku |last2=Suzuki |first2=Nao |last3=Yoneda |first3=Masahiro |last4=Takeshita |first4=Toru |last5=Hirofuji |first5=Takao |title=Effect of mouth cleaning with hinokitiol-containing gel on oral malodor: a randomized, open-label pilot study |journal=Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology |date=October 2013 |volume=116 |issue=4 |pages=433–439 |doi=10.1016/j.oooo.2013.05.021|pmid=23969334 }}</ref> and [[essential oil]]s.<ref>{{cite journal |last1=Scully |first1=C |title=Halitosis. |journal=BMJ Clinical Evidence |date=18 September 2014 |volume=2014 |pmid=25234037|pmc=4168334 }}</ref> [[Listerine]] is one of the well-known mouthwash products composed of different essential oils.<ref>{{cite book|last1=Newton|first1=David|title=Trademarked: a history of well-known brands, from Aertex to Wright's Coal Tar|date=2008|publisher=Sutton Publishing|location=Stroud|isbn=978-0-7509-4590-5|url=https://books.google.com/books?id=HekTDQAAQBAJ&pg=PT447}}</ref> Other formulations containing herbal products and probiotics have also been proposed.<ref>{{cite journal |last1=Prasad |first1=Monika |title=The Clinical Effectiveness of Post- Brushing Rinsing in Reducing Plaque and Gingivitis: A Systematic Review |journal=Journal of Clinical and Diagnostic Research |date=2016 |volume=10 |issue=5 |pages=ZE01-7 |doi=10.7860/JCDR/2016/16960.7708|pmid=27437376 |pmc=4948552 }}</ref> Cetylpyridinium chloride and chlorhexidine can temporarily stain teeth.

===Underlying disease===
If [[gum disease]] and [[Tooth decay|cavities]] are present, it is recommended that these be treated.<ref name=Kap2016/>

If diseases outside of the mouth are believed to be contributing to the problem, treatment may result in improvements.<ref name=Kap2016/>

[[Counselling]] may be useful for those who falsely believe that they have bad breath.<ref name=Kap2016/>

== Epidemiology ==
It is difficult for researchers to estimate the prevalence of halitosis in the general population for several reasons. Firstly, halitosis is subject to societal taboo and stigma, which may impact individuals' willingness to take part in such studies or to report accurately their experience of the condition. Secondly, there is no universal agreement about what diagnostic criteria and what detection methods should be used to define which individuals have halitosis and which do not. Some studies rely on self-reported estimation of halitosis, and there is contention as to whether this is a reliable predictor of actual halitosis or not. In reflection of these problems, reported epidemiological data are widely variable.<ref>{{cite journal|last=Cortelli|first=JR|author2=Barbosa, MD |author3=Westphal, MA |title=Halitosis: a review of associated factors and therapeutic approach.|journal=Brazilian Oral Research|year=2008|volume=22|issue=Suppl 1 |pages=44–54|pmid=19838550|doi=10.1590/s1806-83242008000500007|doi-access=free}}</ref>

== History, society and culture ==
The earliest known mention of bad breath occurs in ancient Egypt, where detailed recipes for toothpaste were made before the [[Egyptian pyramids|Pyramid]]s were built. The 1550 BC [[Ebers Papyrus]] describes tablets to cure bad breath based on [[incense]], [[cinnamon]], [[myrrh]] and [[honey]].<ref name="What's The Story?">{{cite web|url=http://www.smiledentaljournal.com/index.php?option=com_content&view=article&id=134%3Abad-breath-whats-the-story&catid=44&Itemid=110|title=Bad breath: What's The Story?|last=Tayara|first=Rafif|author2=Riad Bacho|archive-url=https://web.archive.org/web/20130324075756/http://www.smiledentaljournal.com/index.php?option=com_content&view=article&id=134%3Abad-breath-whats-the-story&catid=44&Itemid=110|archive-date=24 March 2013|url-status=live|access-date=13 August 2012}}</ref> [[Hippocratic Corpus|Hippocratic medicine]] advocated a mouthwash of red wine and spices to cure bad breath.<ref>[[Hippocratic Corpus]]</ref>  Alcohol-containing mouthwashes are now thought to exacerbate bad breath as they dry the mouth, leading to increased microbial growth. The [[Hippocratic Corpus]] also describes a recipe based on marble powder for females with bad breath.<ref name="Book: bad breath research perspectives">{{cite book|editor-last=Rosenberg|editor-first=Mel|title=Bad breath: research perspectives.|year=1998|publisher=Ramot Publishing|location=Tel Aviv|isbn=978-965-274-173-8|edition=2.}}</ref> The Ancient Roman physician [[Pliny the Elder|Pliny]] wrote about methods to sweeten the breath.<ref>{{cite web|last=Eggert|first=F-Michael|title=Bad Breath is an Ancient Concern!|url=https://www.ualberta.ca/~feggert/BREATH_2.HTM|access-date=13 August 2012|url-status=live|archive-url=https://web.archive.org/web/20131105141043/http://www.ualberta.ca/~feggert/BREATH_2.HTM|archive-date=5 November 2013}}</ref>

Ancient Chinese emperors required visitors to chew [[clove]] before an audience.<ref name="What's The Story?" /> The [[Talmud]] describes bad breath as a disability, which could be grounds for legal breaking of a marriage license.<ref name="Winkel 2008">{{cite book|title=Clinical periodontology and implant dentistry|year=2008|publisher=Blackwell Munksgaard|location=Oxford|isbn=978-1-4051-6099-5|pages=1324–1340|author=Winkel EG|edition=5th|veditors=Lindhe J, Lang NP, Karring T |chapter=Chapter 60: Halitosis Control}}</ref> Early Islamic theology stressed that the teeth and tongue should be cleaned with a [[siwak]], a stick from the plant [[Salvadora persica]] tree.<ref name="Winkel 2008" /> This traditional chewing stick is also called a Miswak, especially used in [[Saudi Arabia]], and is essentially like a natural toothbrush made from twigs.<ref name="What's The Story?" /> During the [[Renaissance]] era, [[Laurent Joubert]], doctor to King [[Henry III of France]] stated that bad breath is "caused by dangerous [[miasma theory|miasma]] that falls into the lungs and through the heart, causing severe damages".<ref name="What's The Story?" />

In [[s:Author:B. G. Jefferis|B. G. Jefferis]] and [[s:Author:J. L. Nichols|J. L. Nichols']] "[[s:Searchlights on Health/How to Cure Apoplexy, Bad Breath and Quinsy|Searchlights on Health]]" (1919), the following recipe is offered: "[One] teaspoonful of the following mixture after each meal: One ounce chloride of soda, one ounce liquor of potassa, one and one-half ounces phosphate of soda, and three ounces of water."

In the present day, bad breath is one of the biggest social taboos. The general population places great importance on the avoidance of bad breath, illustrated by the annual $1 billion that consumers in the United States spend on deodorant-type mouth (oral) rinses, mints, and related over-the-counter products.<ref name="Carranza 2012">{{cite book|title=Carranza's clinical periodontology|year=2012|publisher=Elsevier/Saunders|location=St. Louis, Mo.|isbn=978-1-4377-0416-7|pages=331–338|vauthors=Quirynen M, Van den Velde S, Vandekerckhove B, Dadamio J |edition=11th|veditors=Newman MG, Takei HH, Klokkevold PR, Carranza FA |chapter=Chapter 29: Oral Malodor}}</ref> Many of these practices are merely short term attempts at masking the odour. Some authors have suggested that there is an evolutionary basis to concern over bad breath. An instinctive aversion to unpleasant odours may function to detect spoiled food sources and other potentially invective or harmful substances.<ref name="Hoover 2010">{{cite journal|last=Hoover|first=KC|title=Smell with inspiration: the evolutionary significance of olfaction.|journal=American Journal of Physical Anthropology|year=2010|volume=143|issue=Suppl 51 |pages=63–74|pmid=21086527|doi=10.1002/ajpa.21441|doi-access=free}}</ref> Body odours in general are thought to play an important role in mate selection in humans,<ref>{{cite journal|last=Grammer|first=K|author2=Fink, B |author3=Neave, N |title=Human pheromones and sexual attraction.|journal=European Journal of Obstetrics, Gynecology, and Reproductive Biology|date=Feb 1, 2005|volume=118|issue=2|pages=135–42|pmid=15653193|doi=10.1016/j.ejogrb.2004.08.010}}</ref> and unpleasant odour may signal disease, and hence a potentially unwise choice of mate. Although reports of bad breath are found in the earliest medical writings known, the social stigma has likely changed over time, possibly partly due to sociocultural factors involving advertising pressures. As a result, the negative psychosocial aspects of halitosis may have worsened, and psychiatric conditions such as halitophobia are probably more common than historically. There have been rare reports of people committing suicide because of halitosis, whether there is genuine halitosis or not. {{citation needed|date=April 2025}}

=== Etymology ===
{{wiktionary}}
The word halitosis is derived from the Latin word ''halitus'', meaning 'breath', and the Greek suffix ''-osis'' meaning 'diseased' or 'a condition of'.<ref>{{OEtymD|halitosis}}</ref> With modern [[consumerism]], there has been a complex interplay of advertising pressures and the existing evolutionary aversion to malodour. Contrary to the popular belief that [[Listerine]] coined the term ''halitosis'', its origins date to before the product's existence,<ref>[http://www.merriam-webster.com/dictionary/halitosis Halitosis&nbsp;– Definition and More from the Free Merriam-Webster Dictionary] {{webarchive|url=https://web.archive.org/web/20111115093904/http://www.merriam-webster.com/dictionary/halitosis |date=2011-11-15 }}. Merriam-webster.com. Retrieved on 2011-10-10</ref> being coined by physician Joseph William Howe in his 1874 book ''The Breath, and the Diseases Which Give It a Fetid Odor'',<ref>{{Cite book|last=Howe|first=Joseph W.|url=https://babel.hathitrust.org/cgi/pt?id=loc.ark:/13960/t4hm6c99z&seq=26|title=The Breath, and the Diseases Which Give It a Fetid Odor|publisher=D. Appleton & Company|year=1874|location=New York|page=20}}</ref><ref>{{Cite web|last=Katz|first=Harold|date=January 12, 2011|title=The Origin and Evolution of|url=http://www.therabreath.com/articles/oral-care-tips-and-advice/the-origin-and-evolution-of-halitosis-2545/|archive-url=https://web.archive.org/web/20161125043638/http://www.therabreath.com/articles/oral-care-tips-and-advice/the-origin-and-evolution-of-halitosis-2545/|archive-date=November 25, 2016|access-date=2016-11-24|website=Therabreath}}</ref> although it only became commonly used in the 1920s when a [[Listerine#History|marketing campaign]] promoted Listerine as a solution for "chronic halitosis". The company was the first to manufacture mouthwashes in the United States. According to [[Freakonomics]]:{{blockquote| Listerine "...was invented in the nineteenth century as a powerful surgical antiseptic. It was later sold, in distilled form, as both a floor cleaner and a cure for [[gonorrhea]]. But it wasn't a runaway success until the 1920s, when it was pitched as a solution for "chronic halitosis"— a then obscure medical term for bad breath.  Listerine's new ads featured forlorn young women and men, eager for marriage but turned off by their mate's rotten breath.  "Can I be happy with him in spite of ''that''?" one maiden asked herself.  Until that time, bad breath was not conventionally considered such a catastrophe, but Listerine changed that.  As the advertising scholar James B. Twitchell writes, "Listerine did not make mouthwash as much as it made halitosis." In just seven years, the company's revenues rose from $115,000 to more than $8 million."<ref>{{Cite book  | title = Freakonomics: A Rogue Economist Explores The Hidden Side Of Everything  | first1 = Steven D.  | last1 = Levitt  | author-link1 = Steven D. Levitt  | first2 = Stephen J.  | last2 = Dubner  | author-link2 = Stephen J. Dubner  | publisher = [[HarperCollins]]  | year = 2009  | location = [[New York City|New York]]  | page = [https://books.google.com/books?id=66Dm4p1wxqUC&pg=PA87 87]  | oclc = 502013083  | isbn = 978-0-06-073133-5  | url = http://freakonomicsbook.com/  | url-status = live  | archive-url = https://web.archive.org/web/20110213100828/http://freakonomicsbook.com/  | archive-date = 2011-02-13  }}</ref>}}

=== Alternative medicine ===
According to traditional [[Ayurvedic]] medicine, chewing [[areca nut]] and [[betel]] leaf is a remedy for bad breath.<ref>Naveen Pattnaik, ''The Tree of Life''</ref> In South Asia, it was a custom to chew areca or betel nut and betel leaf among lovers because of the breath-freshening and stimulant drug properties of the mixture. Both the nut and the leaf are mild stimulants and can be addictive with repeated use. The betel nut will also cause [[dental decay]] and red or black staining of teeth when chewed.<ref>{{cite journal|last=Norton|first=SA|title=Betel: consumption and consequences.|journal=Journal of the American Academy of Dermatology|date=January 1998|volume=38|issue=1|pages=81–8|pmid=9448210|doi=10.1016/s0190-9622(98)70543-2}}</ref> Both areca nut and betel leaf chewing, however, can cause [[premalignant lesion]]s such as [[leukoplakia]] and [[submucous fibrosis]], and are recognized risk factors for oral and [[oropharyngeal]] [[squamous cell carcinoma]] ([[oral cancer]]).<ref>{{cite journal|last=Warnakulasuriya|first=S|author2=Trivedy, C |author3=Peters, TJ |title=Areca nut use: an independent risk factor for oral cancer.|journal=BMJ (Clinical Research Ed.)|date=Apr 6, 2002|volume=324|issue=7341|pages=799–800|pmid=11934759|doi=10.1136/bmj.324.7341.799|pmc=1122751}}</ref>

Practitioners and purveyors of [[alternative medicine]] sell a vast range of products that claim to be beneficial in treating halitosis, including dietary supplements, vitamins, and oral probiotics. Halitosis is often claimed to be a symptom of "[[Candidiasis#Alternative medicine|candida hypersensitivity syndrome]]" or related diseases, and is claimed to be treatable with [[antifungal medication]]s or alternative medications to treat fungal infections.

== Research ==
In 1996, the International Society for Breath Odor Research (ISBOR) was formed to promote multidisciplinary research on all aspects of breath odours.{{cn|date=January 2025}}

== References ==
{{Reflist}}

== External links ==
{{Medical resources
|  DiseasesDB     = 5603
|  ICD10          = {{ICD10|R|19|6|r|10}}
|  ICD9           = {{ICD9|784.99}}
|  ICDO           = 
|  OMIM           = 
|  MedlinePlus    = 003058
|  eMedicineSubj  = article
|  eMedicineTopic = 867570
|  MeshID         = D006209
}}
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[[Category:Symptoms and signs: Digestive system and abdomen]]
[[Category:Oral hygiene]]
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