This is an important question because even patients who are very meticulous about brushing and flossing may still suffer from bad breath that is oral in its origin. This is because the tongue is believed to be one of the main sources of oral odor. Most people have never been taught to brush their tongue. Furthermore, mo st of these mouthrinses contain a high percentage of alcohol which when used too frequently will tend to dry out the mouths' tissue. Dryness of the mouth is almost always associated with halitosis.
Many medications can cause dryness.
Some also have a distinct odor of their own which enters the breath via the lungs. I love spicy food. Many spices like garlic and onions affect the breath. In the digestive system the by-products of these spices are able to enter into the bloodstream. From there they enter the breath by being excreted from the lungs.