What causes bad breath?

Yes I know that if you eat a whole onion on your cheeseburger, or if you douse your cheesy bread with garlic, you are going to have bad breath and others will suffer. But what causes other types of bad breath…like morning breath? After researching this topic, I found that while you are sleeping your mouth becomes very dry which is called xerostomia. Your salivary glands are much less active while asleep and the bacteria flourish causing gross morning breath. Other causes of bad breath besides food of course, are bad oral hygiene, things such as tobacco and cigarettes, and also other health conditions. For information on foods that help fight bad breath visit this website. http://ezinearticles.com/?5-Important-Foods-To-Avoid-Bad-Breath&id=5270506