Bad breath, also known as halitosis, is a symptom in which a
noticeably unpleasant odor is present on the breath. It can result
in anxiety among those affected. It is also associated with
depression and symptoms of obsessive compulsive disorder.
Concerns of bad breath may be divided into genuine and non-genuine
cases. Of those who have genuine bad breath, about 85% of cases
come from inside the mouth. The remaining cases are believed to be
due to disorders in the nose, sinuses, throat, lungs, esophagus, or
stomach. Rarely, bad breath can be due to an underlying medical
condition such as liver failure or ketoacidosis. Non-genuine cases
occur when someone feels they have bad breath but someone else cannot
detect it. This is estimated to make up between 5% and 72% of
The treatment depends on the underlying cause. Initial efforts may
include tongue cleaning, mouthwash, and flossing. Tentative
evidence supports the use of mouthwash containing chlorhexidine or
cetylpyridinium chloride. While there is tentative benefit from
the use of a tongue cleaner it is insufficient to draw clear
conclusions. Treating underlying disease such as gum disease, tooth
decay, or gastroesophageal reflux disease may help.
be useful in those who falsely believe that they have bad breath.
Estimated rates of bad breath vary from 6% to 50% of the
population. Concern about bad breath is the third most common
reason people seek dental care, after tooth decay and gum
disease. It is believed to become more common as people age.
Bad breath is viewed as a social taboo and those affected may be
stigmatized. People in the United States spend more than $1
billion per year on mouthwash to treat the condition.
1 Signs and symptoms
2 Differential diagnosis
2.1.3 Other causes
2.2 Nose and sinuses
2.6 Systemic diseases
2.7 Delusional halitosis
3.1 Self diagnosis
4.1 Mechanical measures
4.3 Underlying disease
6 History, society and culture
6.2 Alternative medicine
9 External links
Signs and symptoms
Bad breath is when a noticeably unpleasant odor is believed to be
present on the breath. It can result in anxiety among those affected.
It is also associated with depression and symptoms of obsessive
In about 90% of genuine halitosis cases, the origin of the odor is in
the mouth itself. This is known as intra-oral halitosis, oral
malodor or oral halitosis.
The most common causes are odor producing biofilm on the back of the
tongue, below the gumline, and in the pockets created by gum disease
between teeth and the gums. This biofilm results in the production of
high levels of foul odors. The odors are produced mainly due to the
breakdown of proteins into individual amino acids, followed by the
further breakdown of certain amino acids to produce detectable foul
gases. Volatile sulfur compounds are associated with oral malodor
levels, and usually decrease following successful treatment. Other
parts of the mouth may also contribute to the overall odor, 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
dental work, food-impaction areas in between the teeth, abscesses, and
unclean dentures. Oral based lesions caused by viral infections
like herpes simplex and 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, onions, meat, fish, and cheese),
smoking, and alcohol consumption. Since the mouth is exposed to
less oxygen[medical citation needed] and is inactive during the night,
the odor is usually worse upon awakening ("morning breath"). Bad
breath may be transient, often disappearing following eating,
drinking, tooth brushing, flossing, or rinsing with specialized
Bad breath may also be persistent (chronic bad breath),
which affects some 25% of the population in varying degrees.
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 bacteria produce malodorous compounds and fatty
acids, and account for 80 to 90% of all cases of mouth-related bad
breath. Large quantities of naturally occurring bacteria are often
found on the posterior 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,
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 putrescent smell of indole, skatole,
polyamines, or the "rotten egg" smell of 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 "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 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.
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 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 periodontal
diseases in causing bad breath. However, advanced periodontal disease
is a common cause of severe halitosis. Waste products from the
anaerobic bacteria growing below the gumline (subgingival) have a foul
smell and have been clinically demonstrated to produce a very intense
bad breath. Removal of the subgingival calculus (i.e. tartar or
hard plaque) and friable tissue has been shown to improve mouth odor
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 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 probe. Indeed, VSC 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 suffer from halitosis than the
general population, the halitosis symptom was shown to be more
strongly associated with 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 malodor that is detectable by others.
Other less common reported causes from within the mouth
Deep carious lesions (dental decay) – which cause localized
food impaction and stagnation
Recent dental extraction sockets – fill with blood clot, and
provide an ideal habitat for bacterial proliferation
Interdental food packing – (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 malodorous 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 interdental brush
Acrylic dentures (plastic false teeth) – 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
Menstrual cycle – at mid cycle and during menstruation,
increased breath VSC were reported in women.
Smoking – Smoking is linked with periodontal disease, which is
the second most common cause of oral malodor. Smoking also has many
other negative effects on the mouth, from increased rates of dental
decay to premalignant lesions and even oral cancer.
Volatile foods – e.g. onion, garlic, durian, cabbage,
cauliflower and radish. Volatile foodstuffs may leave malodorous
residues in the mouth, which are the subject to bacterial putrefaction
and VSC release. However, volatile foodstuffs may also cause
halitoisis via the blood borne halitosis mechanism.
Medication – 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 nostrils has a pungent odor
that differs from the oral odor. Nasal odor may be due to sinus
infections or foreign bodies.
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.
There is disagreement as to the proportion of halitosis cases which
are caused by conditions of the tonsils. Some claim that the
tonsils are the most significant cause of halitosis after the
mouth. According to one report, approximately 3% of halitosis
cases were related to the tonsils. Conditions of the tonsils which
may be associated with halitosis include chronic caseous tonsillitis
(cheese-like material can be exuded from the tonsillar crypt orifi),
tonsillolithiasis (tonsil stones), and less commonly peritonsillar
abscess, actinomycosis, fungating malignancies, chondroid choristoma
and inflammatory myofibroblastic tumor.
The lower esophageal sphincter, which is the valve between the stomach
and the esophagus, may not close properly due to a hiatal hernia or
GERD, allowing acid to enter the esophagus and gases to escape to the
Zenker's diverticulum may also result in halitosis due to
aging food retained in the esophagus.
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 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 odor.
In the case of allyl methyl sulfide (the byproduct of garlic's
digestion), odor does not come from the stomach, since it does not get
There are a few systemic (non-oral) medical conditions that may cause
foul breath odor, but these are infrequent in the general population.
Such conditions are:
Fetor hepaticus: an example of a rare type of bad breath caused by
chronic liver failure.
Lower respiratory tract infections (bronchial and lung infections).
Kidney infections and kidney failure.
Trimethylaminuria ("fish odor syndrome”).
Metabolic conditions, e.g. resulting in elevated blood dimethyl
Individuals afflicted by the above conditions often show additional,
more diagnostically conclusive symptoms than bad breath alone.
One quarter of the people seeking professional advice on bad breath
have an exaggerated concern of having bad breath, known as
halitophobia, delusional halitosis, or as a manifestation of 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
Scientists have long thought that smelling one's own breath odor 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.
One popular home method to determine the presence of bad breath is to
lick the back of the wrist, let the saliva dry for a minute or two,
and smell the result. This test results in overestimation, as
concluded from research, and should be avoided. 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 polyamines and sulfur
compounds on tongue swabs are now available, but there are few studies
showing how well they actually detect the odor. Furthermore, since
breath odor changes in intensity throughout the day depending on many
factors, multiple testing sessions may be necessary.
If bad breath is persistent, and all other medical and dental factors
have been ruled out, specialized testing and treatment is required.
Hundreds of dental offices and commercial breath clinics now claim to
diagnose and treat bad breath. They often use some of
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
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
Gas chromatography: portable machines, such as the OralChroma, are
currently being introduced. This technology is specifically designed
to digitally measure molecular levels of the three major VSCs in a
sample of mouth air (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 computer
BANA test: this test is directed to find the salivary levels of an
enzyme indicating the presence of certain halitosis-related bacteria.
β-galactosidase test: salivary levels of this enzyme were found to be
correlated with oral malodor.
Although such instrumentation and examinations are widely used in
breath clinics, the most important measurement of bad breath (the gold
standard) is the actual sniffing and scoring of the level and type of
the odor carried out by trained experts ("organoleptic measurements").
The level of odor is usually assessed on a six-point intensity
Two main classification schemes exist for bad breath, although neither
are universally accepted.
The Miyazaki et al. classification was originally described in 1999 in
a Japanese scientific publication, and has since been adapted to
reflect North American society, especially with regards
halitophobia. The classification assumes three primary divisions
of the halitosis symptom, namely genuine halitosis, pseudohalitosis
and halitophobia. This classification has been suggested to be most
widely used, but it has been criticized because it is overly
simplistic and is largely of use only to dentists rather than other
A. Physiologic halitosis
B. Pathologic halitosis
The Tangerman and Winkel classification was suggested in Europe in
2002. 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.
A. Blood borne halitosis
(i) Systemic diseases
(ii) Metabolic diseases
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 odor into 3 groups:
"Sulfurous or fecal" caused by volatile sulfur compounds (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.
Based on the strengths and weaknesses of previous attempts at
classification, a cause based classification has been proposed:
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 odor present in all
Efforts may include physical or chemical means to decrease the numbers
of bacteria, products to mask the smell, or chemicals to alter the
odor creating molecules. It is recommended that in those who use
tobacco products stop. Evidence does not support the benefit of
dietary changes or chewing gum.
Brushing the teeth may help. While there is tentative benefit from
tongue cleaning it is insufficient to draw clear conclusions. A
2006 Cochrane review found tentative evidence that it might decrease
levels of odor molecules.
Flossing may be useful.
A 2008 systematic review found that antibacterial mouthrinses may
help. Mouthwashes often contain antibacterial agents including
cetylpyridinium chloride, chlorhexidine, zinc gluconate, essential
oils, hydrogen peroxide, and chlorine dioxide. Cetylpyridinium
chloride and chlorhexidine can temporarily stain teeth.
If gum disease and cavities are present, it is recommended that these
If diseases outside of the mouth are believed to be contributing to
the problem, treatment may result in improvements.
Counselling may be useful in those who falsely believe that they have
It is difficult for researchers to make estimates of the prevalence of
halitosis in the general population for several reasons. Firstly,
halitosis is subject to societal taboo and stigma, which may impact
individual's 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.
History, society and culture
The earliest known mention of bad breath occurs in ancient Egypt,
where detailed recipes for toothpaste are made before the Pyramids are
built. The 1550 BC
Ebers Papyrus describes tablets to cure bad breath
based on incense, cinnamon, myrrh and honey. Hippocratic medicine
advocated a mouthwash of red wine and spices to cure bad breath.
Note that alcohol-containing mouthwashes are now thought to exacerbate
bad breath as they dry the mouth, leading to increased microbial
Hippocratic Corpus also describes a recipe based on marble
powder for female bad breath sufferers. The Ancient Roman
physician Pliny wrote about methods to sweeten the breath.
Ancient Chinese emperors required visitors to chew clove before an
Talmud describes bad breath as a disability, which
could be grounds for legal breaking of a marriage license. Early
Islamic theology stressed that the teeth and tongue should be cleaned
with a siwak, a stick from the plant
Salvadora persica tree. This
traditional chewing stick is also called a Miswak, especially used in
Saudi Arabia, an essentially is like a natural toothbrush made from
twigs. During the
Renaissance era, Laurent Joubert, doctor to King
Henry III of France
Henry III of France states bad breath is "caused by dangerous miasma
that falls into the lungs and through the heart, causing severe
In B. G. Jefferis and J. L. Nichols' "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. Many of these practices are
merely short term attempts at masking the odor. Some authors have
suggested that there is an evolutionary basis to concern over bad
breath. An instinctive aversion to unpleasant odors may function to
detect spoiled food sources and other potentially invective or harmful
substances. Body odors in general are thought to play an important
role in mate selection in humans, and unpleasant odor 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.
The word halitosis is derived from the Latin word halitus, meaning
'breath', and the Greek suffix -osis meaning 'diseased' or 'a
condition of'. With modern consumerism, there has been a complex
interplay of advertising pressures and the existing evolutionary
aversion to malodor. Contrary to the popular belief that Listerine
coined the term halitosis, its origins date to before the product's
existence, being coined by physician Joseph William Howe in his
1874 book The Breath, and the Diseases Which Give It a Fetid Odor,
although it only became commonly used in the 1920s when a marketing
Listerine as a solution for "chronic halitosis". The
company was the first to manufacture mouth washes in the United
States. According to Freakonomics:
Listerine "...was invented in the nineteenth century as 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
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."
According to traditional
Ayurvedic medicine, chewing areca nut and
betel leaf is a remedy for bad breath. 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. Both areca nut and betel
leaf chewing, however, can cause premalignant lesions such as
leukoplakia and submucous fibrosis, and are recognised risk factors
for oral and oropharyngeal squamous cell carcinoma (oral cancer).
Other traditional remedies for halitosis include guava leaves in
Thailand, eggshells in China, parsley in Italy, and urine-based mouth
rinse in certain European cultures.
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 "candida
hypersensitivity syndrome" or related diseases, and is claimed to be
treatable with antifungal medications or alternative medications to
treat fungal infections.
In 1996, the International Society for
Odor Research (ISBOR)
was formed to promote multidisciplinary research on all aspects of
breath odors. The eighth international conference on breath odor took
place in 2009 in Dortmund, Germany, while the ninth was held in 2011
in Salvador da Bahia, Brazil.
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V · T · D
Patient UK: Bad breath
Symptoms and signs: digestive system and abdomen (R10–R19, 787,789)
Blood: Fecal occult blood
Heel tap sign
Fluid wave test