In a recent reaserch clearly says that the main source of bad breath is the tongue. Why? Layers of bacteria can get embedded on it, resulting in foul-smelling Volitlie Sulfer Compounds.
Possible reasons for bad-breath causes like dry mouth (which occurs naturally during sleep, but can also be caused by a glandular condition), as well as certain foods, like onions or garlic.
Post nasal drip, which causes bad breath because bacteria are attracted to the resulting mucus and phlegm.
Daily tongue scraping and brushing your teeth (morning and evening) twice a day can control your bad breath.