The process of chemical digestion starts in the mouth, where saliva begins to break down starches using enzymes. However, the majority of chemical digestion occurs in the stomach and large intestines.
Chemical digestion is the bodily process used to break down food at a molecular level through the use of enzymes and other digestive secretions. When people see, smell or even begin to think about food, their bodies start producing excess saliva in preparation for a coming meal. The saliva aids in digestion by breaking down starches and carbohydrates so that they can more readily be processed and absorbed by the rest of the digestive system.