If you don't drink enough water, your body can become dehydrated. This reduces saliva production, which is crucial for washing away bacteria in your mouth. A dry mouth allows odour-causing bacteria to thrive on your teeth and tongue, leading to that funky breath smell. The simple fix? Keep a water bottle handy and stay hydrated all day to combat this common cause of bad breath. Carrying a water bottle and staying hydrated throughout the day is a simple but powerful way to combat bad breath caused by a dry mouth.