Main Function of the Excretory System. The excretory system is responsible for removing wastes produced by the body. These wastes must be removed, or excreted, in order for the body to remain healthy. The human excretory system includes the skin, the kidneys, the large intestines and the liver. Each of these organs helps the body to excrete or eliminate waste that the body takes in when it eats or drinks something, or that the body produces during metabolic or life functions.