Digestion is the mechanical and chemical breaking down of food into smaller components, usually inside a body, to a form that can be absorbed, for instance, by a blood stream.  The food enters the mouth, being chewed by teeth, and broken down by the saliva from the salivary glands. Then it travels down the esophagus into the stomach. Acids break down most of the food. The 'leftovers' go through your small intestine, through your large intestine, and comes out as waste.  Learn More