Digestion is the complex biological process by which the body breaks down food into smaller molecules that can be absorbed and used for energy, growth, and repair. It begins in the mouth with chewing and saliva, continues in the stomach where acids and enzymes further break down food, and proceeds through the small intestine where most nutrient absorption occurs. The pancreas, liver, and gallbladder contribute digestive enzymes and bile to aid in the breakdown of fats, proteins, and carbohydrates. The remaining waste products pass into the large intestine for water absorption and eventual elimination. Efficient digestion depends on coordinated muscle movements, enzyme activity, and a healthy gut lining, and disruptions can lead to symptoms such as bloating, indigestion, constipation, diarrhea, or nutrient deficiencies.