The small intestine is longer, but the large intestine is thicker.
The main purpose of the large intestine is to absorb water from the remaining indigestible food matter and to eject the useless waste material from the body. After the digestion in the small intestine which takes 24-30 hours to complete, the large intestine helps in absorbing the water and making the stools solid. It helps in absorbing vitamins made by bacteria that live in the large intestine. It is comprised of the colon and the rectum.