There are a number of reasons you might have bad breath. The most common are listed here:
Bacteria- Bad breath can be caused by the hundreds of types of bad breath-causing bacteria that naturally lives in your mouth. When you eat, bacteria feed on the food left in your mouth and leaves a foul-smelling waste product behind.
Dry Mouth- Saliva is important because it works around the clock to wash out your mouth. If you don’t have enough, your mouth isn’t being cleaned as much as it should be. Dry mouth can be caused by certain medications, salivary gland problems or by simply breathing through your mouth.
Gum Disease-Bad breath can be a warning sign of gum disease.
Food-The list of breath-offending foods is long, and what you eat affects the air you exhale.
Smoking and Tobacco-Smoking stains your teeth, gives you bad breath and puts you at risk for a host of health problems. Tobacco users are also more likely to suffer from gum disease.
Medical Conditions-Mouth infections can cause bad breath. However, if your dentist has ruled out other causes and you brush and floss every day, your bad breath could be the result of another problem, such as a sinus condition, gastric reflux, diabetes, liver or kidney disease. In this case, see your healthcare provider.