Bad breath (halitosis)

Halitosis can be caused by a number of factors
Halitosis can be caused by a number of factors

Halitosis is a dental and medical problem, which may stem from the activity of bacteria in the mouth and poor oral health.

More than just a social dilemma, halitosis is a dental and medical problem, which may stem from the activity of bacteria in the mouth. Most cases of bad breath appear to be due to the breakdown of sulphur-containing proteins by a variety of micro-organisms. These are especially the gram-negative bacteria, which produce foul-smelling gases.

In people with healthy teeth and gums, the odour usually comes from the far back region of the tongue, and grows stronger during talking.

The primary cause of breath odour is VSC, which stands for "volatile sulphide compounds", chemical by-products produced by gram-negative bacteria.

When tissues are inflamed or infected, a concentration of bacteria occurs. The normal rate of tissue regeneration is greatly increased which escalates the protein levels, leading to an increase in the amount of VSC.

Research warns that VSC may have a harmful effect on the normal gum tissue. The compounds are believed to increase the vulnerability of the gum membrane to increased bacterial invasion. If VSC in the mouth can be controlled, so can most mouth odours.

Early periodontal disease may also be controlled by similar measures. (Periodontal disease refers to a group of diseases which affect the periodontium – the tooth, the gum, the bone and the ligament which attaches the tooth to the bone. Greek: peri ="around"and odont ="tooth").

Around a quarter of chronic (i.e. of long duration) cases of halitosis are caused by odours coming from the lungs, alimentary tract, tonsils, adenoids etc. due to medical conditions. These include kidney disease, diabetes, liver disease or the metabolism of certain types of drugs. Dieting may also result in halitosis.

The bacteria that produce the sulphide compounds thrive in dark, oxygen-poor environments like your gums and the back of your tongue where the taste buds are located. These are shaped like tiny mushrooms and provide protective cover for about half the oral population of bacteria.

Other oral factors that can cause bad breath include:

  • Food impacted between teeth
  • Fillings that are old and defective, broken or don't seal the cavity properly
  • Diseases of the dental pulp
  • Oral candidiasis
  • Throat infections
  • Soiled, unhygienic and ill-fitting false teeth

Some non-oral causes may include:

  • Diabetes
  • Kidney failure
  • Infections of the upper respiratory tract and sinuses
  • Nasal cancers
  • Lesions of the nose and back of the throat (nasopharynx)
  • Hiatus hernias
  • Contractions in the throat (oesophageal strictures)
  • Liver failure
  • Foods such as garlic and onions, which are rich sources of VSC

Excessive dieting may also lead to bad breath, due to the increased metabolic breakdown of fats and proteins, and reduced chewing activity resulting in decreased salivary flow.

Postnasal drip is another non-oral factor that can cause halitosis. Mucous drains and coats the back of the tongue and throat, which is exactly where the bacteria live. Since mucous is made up of interlinked strands of protein, the bacteria thrive on breaking them down into odorous and sour-tasting sulphur-type compounds.

Reduced salivation or dry mouth can also be a common cause of bad breath. When your mouth is drier, you have less saliva and there is an increase in the alkalinity of the mouth. Saliva contains oxygen, which keeps your mouth healthy and fresh. With less oxygen an anaerobic environment is created, perfect for bacteria to produce odorous and bitter compounds.

Some cases of dry mouth are naturally occurring, due to breathing for long periods through the mouth, for example, during sleep, or if lip closure is difficult due to improper "bite" of teeth (teeth don't fit properly and lips don't close spontaneously to form a lip-seal). However, most cases of dry mouth are a side-effect of prescription medications (usually those for high blood pressure or depression), alcoholic beverages or mouthwashes containing alcohol.

Bacteria thrive on proteins and therefore the following high-protein foods can contribute to halitosis:

  • Milk, cheese and most other dairy products
  • Fish

In some people, bad breath is associated with gum disease. Your dentist can help prevent and treat gum diseases in various ways, depending on the type and extent of the problem, but your own daily home care can maintain gum health between appointments. Cleaning the spaces between the teeth is of great importance.

One home tip for healthy gums (and fresher breath) is to smell the odour coming from the dental floss, and to work to clean those problem areas more carefully.

Who gets it and who is at risk?
Anyone can suffer from halitosis and most people do at some point in their lives. Poor dental hygiene, smoking, and drinking alcohol or caffeine may worsen the problem.

Symptoms and signs
A few of the common signs of this problem are:

  • A white coating on the surface of the tongue
  • A sour, bitter or metallic taste related to higher acid levels in the mouth
  • Dryness in the mouth, extreme "morning breath", or evidence of thicker saliva
  • High levels of postnasal drip or mucus in the throat
  • An increase in bad breath after eating certain foods, using mouthwashes or hormonal therapies, or during the menstrual cycle

Tiny round white globules known as tonsilloliths are also related to halitosis and sour taste. They are created by sulphur gases produced by bacteria located in the throat area. The sulphur gas mixes with the mucus and thick saliva in the back of your throat and after a period of time, condense into these concentrated, odoriferous globs.

Breathing into your hand to see if you may have bad breath is futile. One problem associated with bad breath is the inability to self-diagnose. People with a normal sense of smell usually becomes desensitised to the smell of their own bodies. Thus, the majority of individuals with halitosis are often unaware of the problem unless someone else tells them so.

If you believe you suffer from halitosis or show any of the above-mentioned signs, seeing a dentist is the first step towards treatment. When you make an appointment, explain in advance that you will be asking for advice about halitosis.

The dentist can sample the area at the back of the tongue using a plastic spoon, gauze or a spatula. The odour coming from the spoon sample may then be compared to the overall odour. The very back of the tongue is an important source of bad breath.

Also, try to go to the dentist's appointment with someone who is familiar with your problem, to help give the dentist an objective picture of how bad the odour really is, how long it has been going on, and when it improves or gets worse.

Since the character of bad breath often varies, a family member or friend can also help determine whether the odour at the time of the appointment resembles, both in character and intensity, the odour that is generally troublesome.

If the dentist knows that the consultation is about bad breath, you may be asked not to eat, drink, smoke, chew gum, suck sweets, and use mouthwashes or breath fresheners for a period before the appointment.

You should also avoid using perfumed cosmetic products prior to the appointment, since these can interfere with the odour assessment. If the dentist is not told about the reason for the consultation beforehand, take these measures and tell him or her that you have prepared for the appointment in this way.

Your dentist will ask questions to help determine the possible cause of the odour, and then compare the odour coming from your mouth and nose. In most cases, the odour comes from the mouth rather than the nose. This is an indication that bacterial activity somewhere in the mouth is responsible.

If the odour comes mostly from the nose, then the nasal passages may be involved, and you might be referred to a general practitioner or an ear, nose and throat specialist.

Halitosis can be prevented in most cases. To combat bad breath, you should first ensure that your oral hygiene is excellent.

  • Visit the dentist regularly for teeth cleaning, and brush your teeth and tongue at least twice daily. As the back of the tongue is known to frequently harbour a population of odour-causing bacteria, it should be scraped/brushed thoroughly.
  • You must also floss daily to remove food particles from between teeth and to prevent build-up of plaque at the gum line.
  • An oral rinse or "mouthwash" can be used, but only to provide extra freshness, not to mask odours which should have been removed by other measures. Mouthwash is only effective for short period of time, and mouthwashes containing alcohol aggravate the problem.

If you wear false teeth, be aware that they are frequently the source of odour. Frequent and thorough cleaning of false teeth is necessary to prevent the accumulation of odour-causing substances.

Most dentists agree that proper brushing helps minimise the risk of tooth decay and gum disease. When it comes to cleaning your teeth, there is a right and a wrong way to brush.

Electric toothbrushes are designed so that the bristles move within the head of the brush, while the head and handle remain stationary. This produces quick, short vibrating strokes that do a superior job in cleaning teeth and stimulating gums. This cleaning is superior to hand cleaning unless the hand cleaning is done properly. There are many electric toothbrush systems on the market but they are not all of the same quality.

Most dental professionals recommend toothbrushes with round heads and soft bristles. Some systems brush the tongue side and the cheek side of the teeth at the same time but these may be less beneficial than those that clean only one side at a time.

Choose an electric toothbrush with a full tuft of soft bristles that rotate gently, but fast enough to be effective. It's also important to choose a brush with a small head that cleans one tooth surface at a time.

Brush at least twice a day with a pea-size drop of fluoride toothpaste or gel using this technique:

  • With your toothbrush at a 45-degree angle, brush the outer and inner surfaces of your teeth at the gum line with short, gentle circular motions, where the circle is so small that only one tooth is brushed at a time.
  • Brush the flat chewing surfaces of your teeth with a back-and-forth motion.
  • Clean the inner surfaces of your front teeth by tilting the brush vertically and using gentle circular motions.
  • Pay special attention to hard-to-reach back teeth and areas where dental work has been performed.
  • Brush your tongue in a back-to-front motion to remove food particles and bacteria.
  • You should take at least two minutes to brush your teeth properly.


Among the wide number of adult halitosis sufferers, the greater majority present oral causes and therefore it becomes the responsibility of the dentist to diagnose and treat these individuals.

Many commercial products are aimed at controlling halitosis by masking it with minty or fruity scents. Mint sweets, chewing gum and most mouthwashes on their own are not powerful enough to combat the foul-smelling VSC.

In the past, bad breath was often considered an incurable affliction. However, in recent years, it has become clear that bad breath is treatable once a correct diagnosis is made.

If the back of the tongue is the problem, the dentist can recommend a method of cleaning the area, either with a toothbrush or a specially designed tongue scraper. Care should be taken to clean the back of the tongue thoroughly yet gently, without inflicting pain or causing sores.

Your dentist may recommend dental treatment, if there are other areas such as cavities in which bacteria and food can become trapped and cause odour.

Experts agree that antibiotics are not the answer. The bacteria involved in this problem are not infectious, and are actually beneficial, assisting with digestion.

Using antibiotics specifically targeted for this group will only temporarily solve the problem for about two days, after which more resistant strains will invade and the halitosis will return.

If you use antibiotics for bad breath and sour tastes, you should be aware that you might end up with an oral yeast infection (thrush). Yeast infections can result from any antibiotic therapy, not just those used for halitosis. Yeast infection can itself also cause halitosis.

Of course, certain circumstances will require the help of antibiotics (e.g. certain periodontal diseases or tonsillitis), and medication can be given to prevent most thrush infections associated with antibiotic therapy.

In general, the most effective way to manage bad breath is by maintaining proper oral hygiene, regular dental cleanings and diligent brushing of the tongue.

Halitosis dos

  • Visit your dentist regularly.
  • Have your teeth cleaned periodically by a dental professional.
  • Floss or otherwise clean between your teeth.
  • Choose unscented floss so that you can detect those areas between your teeth that give off odours, and clean them more carefully.
  • Brush your teeth and gums properly.
  • Ask your dentist to recommend a toothbrush or scraper for your tongue. Gently and thoroughly clean your tongue thoroughly all the way back.  
  • Drink plenty of liquids.
  • Chew sugar-free gum for a minute or two at a time, especially if your mouth feels dry. Chewing parsley, mint, cloves or fennel seeds may also help.
  • Clean your mouth after eating or drinking milk products, fish and meat.
  • False teeth should be brushed daily using dishwashing liquid (the same that you use to clean knives and forks) and a soft brush. If there are stains or tartar on the dentures, have them professionally cleaned.
  • If someone in your family or a close friend has bad breath, find a kind way to let them know.
  • Ask your dentist to recommend a mouthwash that has been shown to be clinically effective in fighting bad breath, and use it just before going to sleep. They are not effective for long periods of time, though.
  • Eat fresh, fibrous vegetables such as carrots.

Halitosis don'ts

  • Don't let your concern about having bad breath run your life. Be proactive.
  • Don't ignore your gums – you can lose your teeth as well as smell bad.
  • Don't drink too much coffee – it may make the situation worse.
  • Don't forget to clean behind the back teeth in each row.
  • Don't brush your tongue with regular toothpaste; it's better to dip your toothbrush in mouthwash for tongue cleaning.
  • Don't run to the gastroenterologist for concerns about bad breath – it usually comes from the mouth and seldom from the stomach.
  • Don't give mouthwash to very young children, as they can swallow it.
  • Don't clean your tongue so hard that it hurts.
  • Don't rely on mouthwash alone – practise complete oral hygiene.

When to call the doctor
If you are showing signs and symptoms of halitosis, or when told so by a friend, make an appointment to see a dentist to help you with the problem.

Revised and reviewed by Professor Bill Evans, BDS Dip Orth(Witwatersrand). Orthodontist: South African Dental Association and Senior Specialist, Department of Orthodontics, University of the Witwatersrand, Johannesburg. February 2015.

Read more:

- Cavities

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