Bad Breath

Bad breath is a common problem

Most of us think that bad breath is simply caused by what food we eat, what we drink or from poor oral hygiene. Many people just pop in a breath mint and think nothing more about. The issue is that bad breath can indicate a much more serious underlying issue and unless we address this issue it will continue to cause problems.

Bad breath also known as halitosis can happen on occasion and can unfortunately become a reoccurring issue. If your bad breath is an ongoing problem it could be because of something more serious.

Is bad breath a sign of poor health?

Halitosis (bad breath) in adults is a common condition that may have oral or non-oral sources and have more than just social consequences.

Halitosis may reflect serious local or systemic conditions, including gingivitis, periodontal disease, diabetic acidosis, hepatic failure, or respiratory infection.

A study of 2000 individuals, published in 2009 (1) asked individuals to attend a free consultation for bad breath and measured a number outcomes. The study showed there are two different causes for individuals with bad breath.

  1. The patient may have a systemic disease

There a number of potential diseases, but the most important ones are liver disease, kidney disease, and uncontrolled diabetes. These three systemic diseases can be picked up by bad breath. Interestingly, each disease even has its own specific smell and it is therefore possible to identify a systemic disease behind an individual’s bad breath (or at the very least order further testing).

What are some of the common smells?

  • A fruity smell may indicate uncontrolled diabetes due to an increase in the proportion of ketones and acetone.
  • A rotten egg smell may indicate that the patient suffers from liver cirrhosis due to an increase in the amount of ammonium in their breath.
  • A fishy smell may indicate that the patient is suffering from kidney insufficiency due to an increase in the amount of urea that gives the smell of fish.
  1. Bad breath may be caused by an increased amount of bacteria and/or an increase in the amount of substrate at one of the lining surfaces in the body.

There are a number of lining surfaces that can be responsible for the creation of bad breath: the ear, nose and throat (ENT) area; the oral cavity; the peridontium (surrounding/supporting tissue around the tooth) and the palate or the tongue. The source can also be the lung area, the alveoli, the bronchi, and as far down as the gastrointestinal tract surface.

If you have an infection, ulceration or tumour in one of these areas, you will have an increase to the amount of the bacteria or the substrate (food for bacteria). The more bacteria you have or the more substrate you have, the more volatile compounds responsible for bad breath will be produced.


  • Source: Australian Dental Association recording of international keynote speaker Professor Marc Quirynen, of the Catholic University in Leuven, speaking on his special areas of research Halitosis.


Quirynen, M., Dadamio, J., Van den Velde, S., De Smit, M., Dekeyser, C., Van Tornout, M. and Vandekerckhove, B. (2009), Characteristics of 2000 patients who visited a halitosis clinic. Journal of Clinical Periodontology, 36: 970–975. doi: 10.1111/j.1600-051X.2009.01478.x

Bad breath is often not even noticed by an individual. In the study referenced above, seven out of ten patients that attended the free consultation were sent by the people around them and didn’t know themselves that they were suffering from bad breath. It seems that one gets acquainted to or used to one’s own bad breath. It’s like a perfume. When you buy a new perfume, in the beginning you smell it, but after some time, you need to apply it more frequently or under a higher concentration because you get used to it.

Bad breath causes

Health problems associated with bad breath include sinus infections, sore throat, post nasal drip, bronchitis, throat infections, diabetes and kidney and liver diseases. Dry mouth which is also called xerostomia can cause bad breath due to the lack of saliva in the mouth. Medications most commonly found to cause bad breath are antihistamines, diuretics, insulin shots, triamterene, and paraldehyde. Other sources of bad breath include:

  • Smoking
  • Chewing tobacco
  • Gum disease
  • Not brushing or flossing enough
  • Low carb diets
  • Plaque buildup
  • Alcoholism
  • Vitamin supplements

Breath mints and chewing gum are just “band-aid” solutions for bad breath and don’t address the underlying cause. To treat bad breath your dentist will conduct a thorough examination to determine the cause and create a treatment plan. If the cause is from bacteria, then treatment can be as simple regular hygienist appointments. If the dentist determines it is something more serious then further tests will need to be conducted.

An examination can be conducted to determine the cause of your bad breath. After the cause is determined, appropriate steps can be taken to improve your situation. If the cause is believed to be systematic disease, further tests can be ordered through referral to a Medical Practitioner. If the cause is from increased bacteria, these issues can be addressed by our dentists or hygienists.

There are many products out there – are these helpful?

If bad breath is due to the second cause above, tongue scraping and professional treatment of gingivitis and periodontitis are the first steps to take. While there are antibiotics and antiseptics available, oral hygiene is crucial for bad breath.

Dr Ron speaking on radio about bad breath (OMIT)

Commonly Asked Questions

For those identified in pathway two, the ENT area was the cause of bad breath in 1.9% of individuals and the respiratory system and gastro systemic diseases were responsible for 2-3%. By far the greatest contributor was the mouth, responsible for 76% of bad breath. Pseudohalitosis is responsible for the remaining 16%.

Pseudohalitosis is the impression or feeling someone has bad breath in the absence of any identified halitosis. These patients need special treatments and often dental practitioners have to involve a psychologist to help.

This is a common misconception.

People often think that bad breath originates from the stomach, but this is not the case. No patients from the above study had malodour from their stomach. The stomach is sealed by a strong sphincter.

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