Digestion is the process of breaking down food into smaller molecules that can be absorbed by the body. It involves three phases: ingestion, digestion, and egestion. Digestion occurs through the actions of the alimentary tract and accessory organs like the liver, gallbladder and pancreas. In the mouth, teeth and saliva begin breaking down food while the esophagus transports food to the stomach where acids and enzymes further break it down. The small intestine completes digestion with help from the pancreas, liver and bile while the large intestine absorbs water before waste is excreted. Common digestive issues include appendicitis, ulcers, constipation, and eating disorders.