The primary cause of halitosis (bad breath) is bacteria laden mucous on the tongue. A good first step to reducing your mouth’s odour is to begin scraping your tongue. There are tongue scrapers available designed specifically for this purpose; or simply brush the length of your tongue with your toothbrush. It is essential that you visit your dentist to determine whether you have gingivitis (gum disease), which is also a leading cause of bad breath. Should the odour persist even after dental attention, there could be a more serious health problem (diabetes, sinus infection, etc.) causing the odour.