Etomoxir, or rac-Ethyl 2-[6-(4-chlorophenoxy)hexyl]oxirane-2-carboxylate, in the form of the dextrorotatory (R)-(+)- enantiomer, is an irreversible inhibitor of carnitine palmitoyltransferase-1 on the inner face of the outer mitochondrial membrane. The biologically active inhibitor – (R)-(+)-etomoxir-Coenzyme A ester – is formed through an intracellular process. The mean concentration for the inhibition of the CPT-1 in the liver, heart, and muscle mitochondria of rats is 20 micromolar/kilogram rac-Etomoxir. (+)-Etomoxir is a colourless solid with a melting point of 38 °C (311 K). The sodium salt of (+)-Etomoxir is water-soluble. The (S)-(-)-enantiomer of Etomoxir does not block CPT-1.