Benzimidazolecarboxanilides of the formula (I) ##STR1## where R.sup.1 and R.sup.2 independently of one another are each hydrogen, chlorine, bromine, alkyl, alkoxy, unsubstituted or alkyl-substituted or alkoxy-substituted phenyl or phenylalkyl, R.sup.3 and R.sup.4 independently of one another are each hydrogen, alkyl, alkyl which is interrupted by one or more oxygen atoms, alkoxy, alkoxy which is interrupted by one or more oxygen atoms, unsubstituted or alkyl-substituted or alkoxy-substituted phenyl, phenylalkoxy, alkanoylamino, benzoylamino, alkanoyloxy or benzoyloxy, n is 0, 1, 2, 3, 4 or 5, X is oxygen, ##STR2## R.sup.5 is hydrogen, alkyl, phenylalkyl, cyanomethyl, aminoethyl, hydroxyethyl, alkylcarbonyl or benzoyl, R.sup.6 is hydrogen, alkyl, phenylalkyl or phennyl and m is from 2 to 8, and the acid addition salts and hydrates of these compounds are stabilizers for organic material, in particular for plastics, such as polyethylene, polypropylene and polyamide.