http://www.oramd.com/bad-breath-treatment.htm To eliminate bad breath, you already know that you have to do more than just cover it up. You need to fight halitosis at its source: the bacteria that grow and collect inside your mouth.
None of the chemicals found in conventional toothpastes and mouthwashes have been proving to eliminate bad breath or the bacteria that causes it.
However, in several countries, studies have been conducted that concluded that the essential oils of peppermint actually work to eliminate bad breath by killing many forms of bacteria, including the kind that causes bad breath.
Source: Treating Bad Breath And Halitosis Symptoms