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Mihael Sok is the Director of The Halitosis Clinic, Ljubljana, Slovenia

Chronic bad breath, also referred to as halitosis or fetor oris, can be a major social handicap for the afflicted individual. Bad breath is considered a chronic condition if it occurs daily and is not relieved by toothbrushing. It has been estimated that one out of ten adults periodically suffers from bad breath of sufficient severity to seek medical help.

Basic Causes Of Bad Breath

Bad breath may have an oral or extraoral etiology, but it usually originates in the patient’s mouth. The strong, disagreeable odor arises from volatile sulfur compounds, mainly hydrogen sulfide (H2S) and mercaptans, produced by the decomposition of proteins (amino acids containing the -SH group) under the influence of anaerobic, Gram-negative bacteria. Proteins are found in the remains of food, in shed and inflammatory cells, in blood and in postnasal drip. Protein decomposition generally takes place in areas where the presence of proteins and anaerobic bacteria is made possible by the normal anatomy (e.g. furrowed mucosa covering the dorsum of the tongue, interdental spaces, valleculae, piriform recesses) or by pathological changes (e.g. gum pockets). Recent studies show that the tongue dorsum is the principal source of volatile sulfur compounds in the oral cavity. Extraoral causes of bad breath are related to diseases of the lungs, esophagus and nose, systemic diseases affecting the liver and kidneys, and diabetes. A considerable proportion of patients presenting with a complaint of chronic bad breath suffer from imaginary halitosis.

New Research Findings Raise New Possibilities

The first clinics concerned with the diagnosis and treatment of halitosis were set up by dentists, general practitioners, oral hygienists and microbiologists in the United States five years ago under different names: halitosis center, halitosis clinic, fresh breath clinic etc. The development of this new branch of health care was made possible by the appearance of portable sulfide monitors (Halimeter®, Interscan Corporation), permitting objective measurement of sulfur compounds in exhaled air, and by new research findings indicating that halitosis rarely results from serious physical illness, the most common sources of the offensive smell being the dorsum of the tongue, the pharynx and diseased periodontal tissues. These findings led to the first efficient methods for the prevention and treatment of chronic bad breath.

The Halitosis Clinic in Ljubljana, established a year and a half ago, is staffed by a dentist and a thoracic surgeon. If necessary, the patient is referred for further evaluation and treatment to a periodontist or an otorhinolaryngologist. Two articles, one published in Ona, women’s weekly supplement of Slovenia’s largest daily newspaper Delo, and the other in the health magazine Zdravje, attracted to the Clinic a considerable number of patients. The aim of this paper is to present our work and its first results.


We have examined 118 patients, who attended the Halitosis Clinic on their own initiative, complaining of chronic bad breath. The patients received prior written instructions to refrain from eating, drinking and toothbrushing for at least 4 hours before the examination. Basic personal and history data were collected through a questionnaire mailed to the patients together with the above instructions. There were 74 women (63%) and 44 men (37%), aged on average 38 years (between 10 and 67 years). The bad breath had been present for an average of 8.5 years (from 8 months to 25 years). Thirty-six percent of the subjects believed that the odor originated in their stomach, 16 percent attributed it to indigestion, 13 percent to the teeth and 9 percent to the sinuses, while 23 percent could not tell where it was coming from. Many patients had one or more additional symptoms. These are summarized in Table 1.

Table 1
Other Symptoms Associated with Halitosis


Percentage of Patients Affected

Bad taste in the mouth


Bleeding gums


Dry mouth


A feeling of pressure in the stomach, heartburn


A feeling of a foreign body in the throat


Previous Treatment And Self-Help Measures

Before coming to the Halitosis Clinic, some patients had seen other specialists, 20 percent more than one. In most cases, the specialists consulted had found no explanation for the bad breath within their field of specialty, yet the problem persisted. Thirty-nine patients (33%) had undergone an E.N.T. examination, 30 (25%) had had one or more gastroscopies, 13 (11%) had seen a periodontist, and five of the 13 had had periodontal surgery. Eight subjects had discussed the problem with their general practitioner and two with a homeopathist. Interestingly, all the patients except one were non-smokers. However, 15 percent were former smokers, most of whom had given up smoking as they believed that this was the cause of their bad breath or aggravated the problem. The patients used various methods to eliminate the odor: they brushed their teeth regularly several times a day and used various mouthrinses, many used irrigators, some chewed gum, others gargled sage tea, one reported using an infusion of dried crushed absinthe leaves to freshen his breath. Despite these measures, the rotten egg odor persisted. A detailed history was obtained from each patient to identify the possible sources and causes of the halitosis.

Examination Of The Oral Cavity

On examining the oral cavity, we were pleasantly surprised by the good oral hygiene maintained by all 118 patients. Their teeth were in good repair without faulty restorations. Traces of soft plaque were found in about a half of the subjects. All were seeing their dentist regularly, but only 43 (36%) had mentioned the problem to the dentist. The others felt that the smell could not be coming from their teeth, considering the attention they were paying to oral hygiene, and so the dentist would be unable to help them. We inspected the tonsillar fossae, the oropharynx and the tongue. The presence and colour of any tongue coatings were noted. The tongue was wiped with a gauze pad, and the smell was assessed with the patient’s cooperation. The most important findings of the oral cavity examinations are presented in Table 2.

Table 2
Major Changes of the Oral Cavity and Pharynx

Oral Cavity Changes

Percentage of Patients Affected

Tongue coating


   —only on the dorsum


   —on more than half of the tongue surface


   —on the entire tongue


Postnasal drip


Periodontal disease


For objective assessment of halitosis we used a Halimeter® (Interscan Corporation, Chatsworth, California, U.S.A.), which measures hydrogen sulfide concentrations in ppb. Three measurements were performed in each subject, two air samples being obtained from the oral cavity and one from the nose. According to the literature, H2S values below 80 ppb were considered normal, causing no disagreeable odor. All normal values were verified by organoleptic appraisal of the subject’s breath.

The average level of H2S in the oral cavity was 158.0 ppb (SD = 85.9) and in the nose it was 67.7 ppb (SD = 15.1). The median H2S values were 120 ppb for the oral cavity and 73 ppb for the nose. H2S levels below 80 ppb were measured in 16 patients (14%), between 81 and 120 ppb in 39 patients (33%), between 121 and 150 ppb in 12 patients (10%), and above 151 ppb in 51 patients (43%).

The 16 patients (14%) with normal H2S levels in their breath were aged on average 36.5 years. Although the measurements clearly showed that they were suffering from imaginary halitosis, only some were prepared to believe that their breath odor was normal.


None of our patients was found to have a significant systemic disease or some other extraoral cause of the bad breath. Seven patients were referred for further evaluation to a periodontologist and four to an otorhinolaryngologist. On completion of the diagnostic assessment, the patients were informed of the cause of their bad breath problem. In most cases, the source of the odor was a coated tongue or postnasal drip. The patients were advised to improve their oral hygiene by regular flossing in addition to thorough brushing of their teeth and gums, and to have dental plaque removed by their dentist.

For the management of tongue coatings and postnasal drip, we developed an efficient regimen of mechanical and chemical cleaning and rinsing of the tongue, pharynx and nasal cavity. It involves the use of tongue scrapers for cleaning the tongue, and a special mouthwash, OrDok, for disinfecting the oral cavity and neutralizing volatile sulfur compounds. The mouthwash, developed on the basis of our own experience and recommendations from the literature, contains a low concentration of chlorhexidine, zinc compounds and vitamins.

The same active ingredients are present in OrDok toothpaste, developed in cooperation with the Henkel Slovenia Company. Sixty-three patients with clear evidence of postnasal drip were prescribed a nasal spray (Aqua di Sirmione), intended to soften and liquefy the thick nasal discharge, mostly resulting from chronic hypertrophic rhinitis. The same nasal spray is used with success in Italy for the treatment of chronic allergic and non-allergic changes in the nose. The patients were advised to practice oral hygiene three times daily and to drink plenty of fluids.


All 102 patients with objective evidence of halitosis (H2S levels above 80 ppb) received appointments for a follow-up examination a month after the initial visit, but only 49 returned to the Clinic at the designated time. At the follow-up examination, the patients were asked to appraise their status. For 18 additional patients these data were obtained through telephone interviews. The patients’ own ratings of their halitosis after a month of treatment are presented in Table 3.

Table 3
Patients’ subjective rating of their halitosis
one month after the first consultation


Percentage of Patients



Slightly improved




Very good


At the follow-up examination, performed on 49 patients, the sulfide monitor test was repeated, and the results were compared with those obtained on initial consultation. When first seen, these 49 patients had had an average H2S level of 160 ppb, but on follow-up examination it was only 83 ppb. So their average H2S level had decreased by nearly a half (48%). At the follow-up visit, normal H2S levels (<80 ppb) were measured in 21 (43%) of the 49 patients. Having suffered from chronic halitosis for many years, these 21 patients were thus completely cured after only a month of treatment.


Until recently, bad breath received little attention in the curricula of most medical and dental schools. This topic was generally mentioned only in connection with serious diseases. Today it is clear that bad breath is not a life-threatening condition, although it can represent a serious social handicap for the afflicted individual. Contrary to popular belief, the disagreeable odor generally does not originate in the stomach or lungs and is rarely caused by indigestion. According to recent research, its most common sources are coatings on the dorsum of the tongue, postnasal drip and periodontal disease.

Our experience shows that halitosis is generally a chronic problem, resulting from changes in the oral cavity. It does not disappear in a week, like a common cold. Its symptoms can be successfully treated, but complete recovery depends on the restoration of balance between the quantity and quality of saliva and oral bacteria, which may require several years of treatment, according to the experience of American centres. The foul-smelling tongue coatings and post-nasal drip develop as a consequence of chronic oral and nasal changes. Their etiology has not been fully explained, but a silent chronic gastro- esophago-pharyngeal reflux is most frequently suggested as the source of all trouble. Proper treatment of periodontal disease and a comprehensive oral hygiene regimen, comprising mechanical and chemical cleaning of the mucosal surfaces of the tongue, pharynx and the nasal cavity, can give good results, restoring a healthy, confident smile to many a patient’s face.

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