Systemic Diseases Causing Bad Breath


When you visit the dentist, he will pay attention to any unusual breath. Sometimes it smells like bad home care, but it can signal that the patient has a systemic disease. The dentist should pick up on this and refer you to your medical doctor.

According to an article on “halitosis” in Wikipedia,

“There are a few systemic (non-oral) medical conditions that may cause foul breath odor, but these are extremely infrequent in the general population. Such conditions are:

  1. Fetor hepaticus: an example of a rare type of bad breath caused by chronic liver failure.
  2. Lower respiratory tract infections(bronchial and lung infections).
  3. Renal infections and renal failure.
  4. Carcinoma.
  5. Trimethylaminuria(“fish odor syndrome”).
  6. Diabetes mellitus.
  7. Metabolic conditions, e.g. resulting in elevated blood dimethyl sulfide.[6]

Individuals afflicted by the above conditions often show additional, more diagnostically conclusive symptoms than bad breath alone.”

Studies done in Canada by Yaegaki and Coil appear in an article “Halitosis: A mirror of systemic and oral health.”   Check out the article for the table of systemic diseases and the nature of the halitosis.


Diabetes mellitus or

impending Diabetic coma:

Acetone, fruity (not detected in well controlled patients)

Liver failure (terminal stage):

Sweetish musty, feculent “amine” odour resembling a fresh cadaver

known as “fetor hepaticus”

Portocaval venous:


Same as fetor hepatic us but characteristically intermittent in nature

for long period of time

Lung abscess, tuberculosis,


Foul, putrefactive

Blood dyscrasias : Resembling decomposed blood of a healing surgical extraction wound

Liver cirrhosis: Resembling decayed blood

Uremia, kidney failure: Ammonia or urine

Toxemia, G.I. disorder, neuro


Varies: poor oral hygiene intensifies the odour.

Fever, dehydration,

Macroglobulinemia (with

salivary gland involvement).:

Odor mainly due to Xerostomia with poor oral hygiene and / or toxic

waste byproducts accumulated in the body.

Syphilis, exanthematous

disease, granuloma venereum:


Wegcners granulomatosis: Necrotic, putrefactive

 See Your Dentist

So the mouth does provide additional clues that could lead the diagnosing in the correct path to diagnosing and subsequently treating the patient’s condition – another reason to keep your dental appointments.