Carcinogenicity and cocarcinogenicity test of phenobarbital sodium in adult BALB/c mice

The carcinogenic and cocarcinogenic action of phenobarbital sodium was investigated in adult BALB/c mice of both sexes when administered alone at a concentration of 0.05% in drinking water for life or after the animals had been treated with a single hydrazine sulphate dose of 5.65 mg. The results demonstrated that phenobarbital sodium is not carcinogenic in this strain of mice, but, since a single dose of hydrazine sulphate was carcinogenic, does not clarify whether it is a cocarcinogen in the lung.