Bad breath comes down to one culprit—bacteria. There are over 600 types of bacteria found in the average mouth and the majority of them gather on the back of your tongue and produce what's known as volatile sulphur compounds (VSCs). This is also the part of the mouth that isn't effectively rinsed with saliva, a natural mouthwash. All you need for fresh breath is good oral hygiene and simple habits. Here's how to head off halitosis all day.