You’re dehydrated
Dehydration is one of the leading bad breath causes, other than poor dental hygiene, according to the Mayo Clinic. Not drinking enough water means food (and the bacteria that feed on it) hangs out in your mouth longer, breeding and heightening the stench. Fortunately, the fix is as simple as the problem: Drink up! Plain H2O is best, but doctors add that sugar-free gum or candies can also help stimulate saliva flow.
You have a serious illness
Bad breath may smell equally stinky to our untrained noses, but according to researchers at the University of Colorado in Boulder, not all bad breath is created equally. The presence of certain, ahem, gasses in your mouth can indicate serious diseases that are also bad breath causes. For instance, excess methylamine may signal liver and kidney disease, ammonia may be a sign of renal failure, elevated acetone levels can indicate diabetes, and nitric oxide levels can be used to diagnose asthma, according to the scientists.
