Lack of carcinogenicity in mice of 4,4-'diaminobenzanilide and 4,4'-diaminoazobenzene, two intermediates used in the manufacture of azo dyes.

4,4'-Diaminobenzanilide and 4,4'-diaminoazobenzene were administered in the diet to BALB/c mice at 100, 300 and 600 ppm dose levels for 60 weeks. The animals were kept under observation until 140 weeks of age when the experiment was terminated. Control and treated groups developed the pattern of tumours usually observed in BALB/c mice. No tumour type at any site was related to treatment.