The main function of the digestive system is to break down food into nutrients, which the body can absorb and utilize for energy, growth, and cellular repair. This complex process begins in the mouth with chewing and the action of saliva, continues in the stomach where food is mixed with digestive juices, and is completed in the small intestine where nutrients are absorbed into the bloodstream. The remaining waste is then processed in the large intestine and expelled from the body. Overall, the digestive system plays a critical role in maintaining the body's health and functionality.