What is the cause of persistent halitosis (bad breath)?

Tongue scraping: Probably the biggest cause of halitosis or bad breath is the accumulation of bacteria on the back of the tongue. Look in the mirror and stick out your tongue you may see a white or yellowish coating on the back of your tongue. Tongue scrapers are available at any drug store that gently remove this layer of bacteria. Follow up with a good mouthwash and you will find a big improvement.

Anaerobic bacteria: Bad breath is caused by billions of bacteria in your mouth, the same bacteria also may cause gum desease. The reason it smells is bacause those bacteria produce gases and other waste in your mouth, and when you exhale, people around you may smell this very characteristic smell.