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W. Steven Pray, Ph.D., R.Ph., Professor of Nonprescription Products and Devices, School of Pharmacy, Southwestern Oklahoma State University, Weatherford, OK          US Pharmacist 24(5), 1999. © 1999 Jobson Publishing



Halitosis, or bad breath, is a very common condition.[1]   Its causes are usually related to the oral cavity. The majority of cases do not represent a major medical problem; however, in some instances halitosis reflects a serious underlying condition that should be screened by a physician. For this reason, individuals who are unaware of their offensive breath should tactfully be made aware of it.


Acknowledgment of Breath Odor


The level of self-awareness of halitosis can range across a wide spectrum. Some people with highly offensive breath seem to have adapted to their own odor through constant exposure of the peripheral receptors, and consider their breath normal.[2,3]  Lack of awareness of the problem can produce a lifetime of wondering why others seem to avoid close conversations.

Others are fully aware of offensive breath and earnestly wish to treat the problem, but may attempt to hide it at all costs. Due to embarrassment, they may never approach the pharmacist; instead, they purchase mouthwashes and breath mints, chew gum constantly, maintain a perceived ‘safe’ distance during conversations, and even employ compensatory measures such as talking out of the side of their mouth, turning their head to the side, or lowering their head slightly to avoid having their offensive breath reach another party.

A final group of patients fear having bad breath in the absence of any detectable odor. This condition is known as halitophobia.[2,4]  Fear of bad breath is similar to other unreasonable fears of body odor or flatulence in that the victim may avoid social contact, become reclusive and, in extreme cases, even commit suicide. Halitophobia may occur because the patient once had a friend or relative who was unaware of his or her bad breath or had been told that his or her breath was bad at some point in the past.


Primary Halitosis


This month’s patient information page discusses some of the nonpathologic causes of halitosis, also known as primary halitosis. At least 47%-90% of the causes of halitosis originate in the oral cavity, rather than arising from systemic problems. Therefore, a dentist is the ideal initial contact for the patient.[1,5]   Primary halitosis is often simply a result of poor oral hygiene. Thus, this month’s patient leaflet recommends that people with halitosis increase the quality of their oral care activities. Frequently, the cause is heavy accumulation of organisms and resultant plaque on the back third of the top of the tongue.[5]  The anterior two-thirds of the tongue is less likely to harbor bacteria because this portion is cleansed every time the person moves it against the hard palate. Friction alone helps prevent any accumulation; however, the back third only contacts the soft palate, which does not produce an effective cleansing action.

Both the occurrence and severity of halitosis are highly individual, depending on such factors as the quantity and type of organisms found on the tongue, as well as other trouble areas such as periodontal pockets, poorly cleansed interdental spaces and the unclean sulcular crevice.[6]   Gram-negative organisms (mostly anaerobes) are the specific bacteria responsible (e.g., Fusobacterium polymorphum and nucleatum, Veillonella alcalescens, Bacteroides fundiliformis, Bacteroides melanogenicus, Klebsiella pneumoniae).[7]  Proliferation of anaerobes in the oral cavity occurs when anaerobic environments are created by plaque accumulation. A plaque layer as thin as 0.1-0.2 mm becomes depleted of oxygen, allowing the Gram-negative anaerobic organisms to replace Gram-positive aerobes and proliferate. As the anaerobes proliferate, they produce a variety of odorous gases, such as volatile sulfur compounds (VSCs).

VSCs have a characteristic foul odor and are what is recognized by many as the major cause of bad breath. VSCs are produced as a natural end-product of bacterial fermentation of sulfur-containing amino acids, including hydrogen sulfide, methyl mercaptan, dimethyl sulfide, and dimethyl disulfide.[8]   Other, nonsulfur compounds that contribute to bad breath include cadaverine, putrescine, indole and skatole (some of these compounds are also responsible for the odor of flatus).[9,10]  

Patients aware of the need to cleanse the back third of the tongue cannot easily do so due to stimulation of the gag reflex. Mouthwash is an effective alternative, but when most patients gargle, they raise the back third of the tongue against the soft palate to prevent aspiration and reflux into the nasal areas. If the patient is taught to make the well-known ‘aaaaahhhhh’ sound while gargling, these normally inaccessible areas of the tongue can be contacted by the mouthwash, enhancing their efficacy.


Serious Oral Causes


Halitosis can reflect the presence of serious medical conditions. Pharmacists must keep in mind that a small group of patients with halitosis require a dental or medical referral.

Oral Conditions:  Extensive dental caries, periodontal disease, or tonsillitis cause a fetid odor accompanied by a bad taste. Rhinitis, ozena, and sinusitis also cause halitosis. The most common cause of bad breath may be chronic gingivitis and periodontal disease. Both have been covered previously in this column.[11]   However, halitosis may indicate many other morbid oral conditions. Oral candidiasis is a possibility, perhaps due to AIDS, diabetes mellitus, or xerostomia. In this case, the change in oral flora is responsible for bad breath.[1]  

Vitamin Deficiencies:  Patients with vitamin/ mineral deficiencies (e.g., vitamin A, vitamin B12, iron, zinc) or other medical conditions may experience stomatitis or glossitis. If either is sufficiently severe, ulcers or fissures may develop, allowing the entrapment of food particles and desquamated cellular debris. Subsequent bacterial putrefaction leads to bad breath.

Cancer:  Cancers, especially pharyngeal or oral tumors, may produce halitosis. The pharmacist must be extremely wary when the patient is obviously a tobacco chewer or dipper, as noted by the foul breath, visible presence of a quid in the patient’s lip or buccal cavity, tooth discolorations, and possible stains from leaking colored saliva on an otherwise white beard.

How to Tell if Bad Breath Originates in the Mouth

The pharmacist may attempt to determine whether a patient’s bad breath originates in the mouth and thus may be treated by oral cleansing and mouthwash, or whether the odor is due to systemic disease, which requires referral to a physician. Bad breath is more likely to originate in the mouth if:[2]  

  • The regular use of a strong mouthwash for a week or so reduces the problem.
  • More careful oral hygiene and tongue brushing reduce the problem.
  • The odor does not exit from the nostrils.
  • The odor intensifies for an observer when the person begins to talk, indicating that the odor is coming from the mouth rather than the nose. To detect this, ask the person to count to 20, smelling the breath while the patient counts.
  • The odor worsens if the mouth is allowed to become dry, as the buffering effect of saliva is lessened and non-sulfur containing gases are liberated when oral tissue is dry.
  • When one licks the hand, there is a detectable odor when the saliva dries.
  • When one scrapes the back of the tongue gently with a disposable plastic spoon, the odor of the residue on the spoon duplicates that of the breath.


Systemic Causes


Only about 10% of cases of halitosis are due to causes outside the oral cavity.[5]   Serious systemic conditions that affect the breath include diabetic ketosis (acetone is present in the breath), liver failure (a mousy odor), cirrhosis (rotten egg-like odor), uremia (a urinous smell), and lung abscess or bronchiectasis (putrid odor). A wide variety of other serious medical conditions can cause halitosis, including gallbladder dysfunction, blood dyscrasias, leukemia, gastric carcinoma, bronchitis, pneumonia, tuberculosis and pulmonary carcinoma. Other, less serious systemic conditions causing halitosis include trimethylaminuria, nasal/sinus infection, tonsillitis, GERD and hiatal hernia.

Diabetes Mellitus:  Pharmacists are perhaps most familiar with diabetes mellitus as a systemic cause of breath alterations. Diabetic ketoacidosis may produce breath that is frequently termed ‘fruity or sweet’ but is more accurately a strange, ketone-like odor reminiscent of various purines and pyrimidines used in organic chemistry laboratories as precursors in the synthesis of various medicinal agents.[1]  

Trimethylaminuria:  An underdiagnosed disorder, trimethylaminuria (TMAU) or fish-odor syndrome, may affect as many as 1% of U.S. citizens, causing an overall body odor and a breath odor that bystanders describe as “fishy.” [5]   In this genetic and incurable disorder the patient cannot properly metabolize choline, leading to an accumulation of trimethylamine, an incomplete degradation product. Unfortunately, trimethylamine’s fishy odor passes to each site of excretion or accumulation, such as sweat, urine, saliva, blood, and the air exhaled through the mouth and nostrils. The patient is urged to moderate or eliminate from the diet foods high in choline, such as broccoli, beans, eggs, legumes, kidney and liver.

Nasal/Sinus Etiologies:  With nasal causes of bad breath, the odor issuing from the nose is stronger than that from the mouth.[2]  The patient may have a nasal infection, nasal polyps, a sinus infection, or had a foreign body inserted into the nose at some previous time.

Gastric Etiologies:  Any medical condition that allows air from the stomach to move up into the esophagus and into the oral cavity may produce halitosis. The most common is gastroesophageal reflux, but hiatal hernia is a possibility.[1]  One clue is that the halitosis is episodic (as are most cases of gastroesophageal reflux), rather than constant. Episodes occur when the lower esophageal sphincter, which is normally closed in the resting state, becomes unable to close properly, allowing gastric odors to reflux. The more serious problem is morbidity or death due to aspiration of gastric contents.

Hepatic Etiologies:  In several cases, the liver is the source of halitosis. Frank liver failure leading to hepatic coma is often signaled by a sweet-smelling amine odor on the breath, the body’s attempt to excrete by-products of sulfur-containing amino acid breakdown.[1]  Cirrhosis may cause a breath odor described as decayed blood or rotten eggs.


Questionable Therapies


Several remedies that have been used to treat bad breath lack evidence of effectiveness. For years, chlorophyll was alleged to possess some ability to stop bad breath when taken internally; however, this has not been proven. Although chlorophyll tablets are still marketed, they are now only approved for diminishing the odor of fecal or urinary excretions.

Another product that has been heavily advertised to eliminate the unpleasant odors from eating spicy foods as well as morning breath is a gelatin capsule containing nothing more than sunflower oil and parsley seed oil. Proclaimed an “all-natural internal breath freshener” this product promises to work in approximately 30 minutes. However, no evidence has been published in the Federal Register demonstrating the effectiveness of these ingredients for helping the breath. Furthermore, it cannot be assumed that an oil-based product that is swallowed will, from its destination in the lower gastrointestinal tract, affect oral malodor. After 30 minutes, the product may have dumped into the small intestine, where its ability to affect oral halitosis is debatable. Clinical studies must be submitted to the FDA for evaluation and publication in the Federal Register before efficacy of this product can be affirmed.


Patient Information – Getting Rid of Bad Breath


Almost everyone has had bad breath, also known as halitosis. Better oral hygiene can help. If the odor is persistent, it is actually a kindness to inform the person, since he or she may be unaware of the problem.

Causes:  Halitosis can be caused by various medical conditions, such as dental caries, gingivitis, oral cancer, hiatal hernia, nasal tumors, bronchitis, pneumonia, diabetes, blood problems and dehydration, among others. The person who becomes aware of the problem can make a medical or dental appointment to discover its source.

Many minor causes of bad breath can be remedied by simple measures. Morning breath, sometimes humorously termed ‘dragon breath’ arises because saliva flow stops during the night, allowing bacteria that produce odorous gases to grow to higher levels. Along the same line, the breath is worse anytime the person has dry mouth (xerostomia), as when taking certain types of medications such as some antidepressants, antihistamines, blood pressure agents, diuretics, narcotics, or anxiety medications. In aging, the salivary glands work less effectively, which is one of several reasons why the breath tends to worsen as people age.

Certain foods are notorious for causing bad breath, including some that contain chemicals excreted by the lungs (e.g., onions, garlic, pastrami and alcohol). Diets high in fat or protein, such as meats and cheeses, cause worse breath than a diet high in fruits and vegetables. ‘Coffee breath’ ensues after drinking coffee.

Oral appliances to alter mouth/tooth structure (such as retainers, braces, orthodontic and pedodontic appliances) hamper food removal after a meal. Be sure to adhere to your doctor’s directions regarding oral cleansing while these appliances are in place. Patients with tooth replacement appliances (such as standard dentures, overdentures, or partial dentures) need to clean the device as directed once daily to prevent bacterial buildup.

Tobacco use of any kind (smoking cigarettes, pipes or cigars; dipping, spitting or chewing of snuff or tobacco) worsens the breath and should be avoided.

Recommendations:  Patients should try improving oral hygiene brushing, flossing, and using a periodontal aid to clean the mouth more thoroughly. If you are unable to brush after eating, chew sugarless gum or at least rinse your mouth with water. Certain mouthwashes may be helpful by reducing the number of bacteria that cause bad breath. Scope mouthwash is used by rinsing or gargling as needed with one capful of the product for 30 seconds. Its bacteria-killing ingredients include alcohol. Children under age 6 years should not use it. Listerine Antiseptic mouthwash is used by rinsing with 4 teaspoonfuls for 30 seconds morning and night for those over age 12 years. Its ingredients include thymol, eucalyptol, methyl salicylate and menthol. You might also try tongue scrapers, available at some pharmacies. For dry mouth, drink plenty of water, try mouthwash and chewing gum specially formulated for dry mouth, and use artificial saliva. If these simple steps fail, a physician appointment is warranted.




  1. Replogle WH, Beebe DK. Halitosis. Am Fam Physician. 1996;53:1215- 1218,1223.
  2. Rosenberg M. Clinical assessment of bad breath: Current concepts. J Am Dent Assoc.1996;127:475-482.
  3. McDowell JD, Kassebaum DK. Diagnosing and treating halitosis. J Am Dent Assoc.1993;124:55-64.
  4. Ben-Aryeh H, Horowitz G, Nir D, et al. Halitosis: An interdisciplinary approach. Am J Otolaryngol. 1998;19:8-11.
  5. Spielman AI, Bivona P, Rifkin BR. Halitosis. NY State Dent J. 1996;62:36-42.
  6. Yaegaki K, Sanada K. Volatile sulfur compounds in mouth air from clinically healthy subjects and patients with periodontal disease. J Periodontal Res. 1992;4 Pt 1:233-238.
  7. Klokkevold PR. Oral malodor: A periodontal perspective. J Calif Dent Assoc.1997;25:153-159.
  8. Richter JL. Diagnosis and treatment of halitosis. Compend Contin Ed Dent. 1996;17:370, 372, 374-376, 378-381, 382, 384, 386.
  9. Pray WS, Nonprescription Product Therapeutics, 1st ed. Baltimore: Lippincott Williams and Wilkins, 1999, 105-113.
  10. Goldberg S, Kozlovsky A, Gordon D, et al. Cadaverine as a putative component of oral malodor. J Dent Res. 1994;73:1168-1172.
  11. Pray WS. Plaque control and dental health. U.S. Pharmacist. 1998; 23(2): 22, 27, 28, 30, 33.