Taurine is one of the sulphur containing amino acids. It is present in most animal tissues and is particularly abundant in oysters, mussels, bovine bile and human breast milk.

In nature its main role is as a substrate in the conjugation of bile acids in the liver. It is abundant in human breast milk and is thought to be important in infant brain and retinal development. Research also suggests that it might also protect cell membranes from toxic substances. In fish it is thought to be an osmoregulator of cell volume.