What is it?
Bad breath is usually caused by bacteria in the mouth and is not usually a sign a general ill health.
Gum disease can cause bad breath. But you could still have bad breath with good oral hygiene, and healthy teeth and gums. The smell then usually comes from the far back of the tongue. It gets stronger when you talk, as your mouth gets drier.
Most adults occasionally suffer from bad breath; perhaps a quarter have it regularly. If you are worried about bad breath, please talk to your dentist.
Source: BDA Leaflet