University of Alberta Bad Breath Research Clinic
Dr. F.-Michael Eggert, DDS, Cert. Periodont., MRCD(c), MSc, PhDcantab

Breath Clinic

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More Facts about Bad Breath Causes.

F-ME 2004

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Some Facts about Bad Breath (Halitosis):

Bad Breath is an Ancient Concern!   
Dental problems were discussed in the earliest medical writings by the ancient Egyptians, Romans and Chinese.
Ancient medical writers such as the famous Greek physician Hippocrates and the Roman physician Pliny wrote about cures for sweetening the breath. As early as 2,000 to 3,000 years ago these writers could have told you about natural remedies such as peppermint for bad breath.     


  • Bad breath (halitosis) is produced by bacteria living in your mouth. These bacteria digest proteins from your saliva and food to produce volatile "smelly" compounds characteristic of bad breath.
  • Smelly compounds released by bacteria include:
    • those with Sulfur in them derived from the sulfur-containing amino acids cysteine and methionine: hydrogen sulfide (rotten eggs), methyl sulfide, dimethyl sulfide.
    • those with Nitrogen in them derived from the amino acids arginine (via ornithine) and lysine: putrescine and cadaverine (rotting meat).
  • Because your saliva flow naturally decreases when you sleep, and some of us even sleep with our mouths open, you will have more bad breath early in the morning. Other times of "inactivity" in your mouth will be in late morning and in the later afternoon when you can anticipate bad breath.
    Table: Causes of Bad Breath  

Action Step1:

  • Have a test done to find out whether you actually have bad breath (halimetry). Some people fear bad breath but do not actually have it! Other people have medically-important causes of bad breath that does not originate in the mouth.
    (These folks need a medical referral).
    Table: Causes of Bad Breath  

Action Step2:

  • Improve oral hygiene (including back of tongue) and perhaps avoid eating some foods without following them by oral hygiene shortly after eating. You can probably not eliminate all of the smell-producing bacteria from your mouth. Mouthrinses might help to mask odours.
    How to control the bacteria that produce odours is the focus of ongoing research in many centres, including ours.


Our main research objective is to develop better methods for monitoring:

  • "Smelly" compounds in mouth air.
  • The bacteria that produce "smelly" compounds to check on the progress of treatment.
  • Treatment outcomes - how well people do with treatment.

If you have specific questions about bad breath please send me an e-mail.
This is an area of tremendous interest, but a lot of the necessary research remains to be done!
NOTE: I cannot recommend specific products or specific clinicians.

© 1996 - 2004 Dr. F-Michael Eggert, my material is copyright with all rights reserved.
Last updated on 08/Sep/2004

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