Metal mercaptides of the formula ##STR1## wherein Me is a metal, oxometal, alkoxymetal or organo-metal cation from the 1st-5th group of the periodic system, n is 0, 1 or 2, m is an integer from 1 to 4, R.sup.1 is hydrogen, alkyl, acyloxymethyl or alkoxymethyl, R.sup.2 is a sterically hindered phenol group, and R.sup.3 is a monovalent organic radical, are stabilizers for organic materials which are sensitive to heat and oxygen. They can be used in particular as stabilizers for chlorine-containing thermoplasts, for elastomers and for lubricants. Preferred cations are organotin cations.