Many people worry about bad breath, either their own or someone else’s. The advertising media have made much of the social stigma arising from ‘offensive breath’ to their own advantage. Bad breath or halitosis may indicate a dental problem, but this may not always be the case.

CAUSES
The odour may be caused by factors in the mouth or by changes occurring in other parts of the body.

Local factors:
· Decaying food particles on or between the teeth
· A coated tongue covered by growing microorganism.
· Unclean dentures
· Smell of tobacco 
· Alcohol
· Gum diseases with pus production involved
· Healing wounds after a surgery or extraction

Causes arising away from the mouth:
· Head cold with infected nasal air passages
· Acute inflammation of air spaces present within the facial bones (often filled with a great deal of pus )
· Tonsillitis.
· Many waste products are broken down from food and drink are excreted through the lungs and this applies to alcoholic drinks as well as pungent foods like onion, garlic etc.
· Diabetes in which the patient has a sweet acetone breath.

Bad breath is not a disease; it is rather a symptom, which indicates the presence of disease either within the mouth or away from the mouth. Odours, which may appear unpleasant to many, may not be the same to some e.g. People in the Mediterranean area are accustomed to the  scent of garlic ,a scent which many people around the world find obnoxious.