Bad breath can be caused by several factors.

Bad breath can be caused by several factors including the most common are the snuff, coffee, garlic and onion. The primary cause of bad breath is the bacterial activity in our mouth, doctors call it halitosis. While we all suffer once the British Dental Association estimates that 25% of adults suffer from it constantly.
Bad breath is also caused by problems with teeth, gums and even problems in the nose as sinusitis and intestinal or stomach problems. Also on alcohol, some antihistamines, nasal sprays and some help produce bad breath because saliva dries. Another cause is less common for people with malnutrition.