Carnitine has a critical role in energy metabolism. Many of the functions of carnitine are not clearly elucidated and many of the regulatory mechanisms governing carnitine metabolism are ill-defined. Carnitine deficiency can be life threatening but may be resolved with carnitine supplementation. Various groups of individuals in addition to those with the classical carnitine deficiency syndrome may require exogenous carnitine. Carnitine nutriture can no longer be ignored.