SA 679;N-[2-methyl-2(methylthio)propionyl]-L-cysteine;N-[2-Methyl-2-(methylthio)propanoyl]-L-cysteine;N-(2-Methyl-2-(methylthio)propionyl)-L-cysteine;(2R)-2-[(2-methyl-2-methylsulfanylpropanoyl)amino]-3-sulfanylpropanoic acid
S-Substituted derivatives of N-(2-mercapto-2-methylpropanoyl)-cysteine which have the formula ##STR1## are useful as a medicine for suppressing liver disorders.