N-acetyl-L-Cysteine ethyl ester is an esterified form of N-acetyl-L-cysteine (NAC; ). It has enhanced cell permeability in isolated perfused rat liver compared to NAC. N-acetyl-L-Cysteine ethyl ester (1 mM) prevents tert-butyl hydroperoxide-induced formation of methemoglobin in isolated human red blood cells. It increases glutathione levels in rat liver, kidney, heart, testis, and brain when administered at a dose of 50 mg/kg twice per day for two weeks. N-acetyl-L-Cysteine ethyl ester reduces increases in plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) levels induced by paracetamol (acetaminophen; ) in rats.