The small intestine is an intestine, and a part of many living beings. It lies between the stomach and the large intestine. In humans over 5 years old, a small intestine may be five to six meters long. It is longer than the large intestine. But, as its diameter is less, its name is small intestine.
It is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large intestine" are often used to describe the entire intestine. This article is primarily about the human gut, though the information about its processes is directly applicable to most placental mammals. The primary function of the small intestine is the absorption of nutrients and minerals found in food. (A major exception to this is cows; for information about digestion in cows and other similar mammals, see ruminants.)