Taurine is present in high concentrations in the human nervous system, especially in the cochlea and retina, but endogenous production via sulphur containing amino acids is barely sufficient to meet these demands, making taurine at least conditionally essential to man. Abnormalities have been detected in physiological markers of hearing and sight both in animals and humans deficient in taurine but the functional relevance of such changes is unknown. Presently, taurine is added to all breast milk substitutes. The evidence of the necessity of this is scant in term infants, however there may be justification for its inclusion in preterm diets.