In previous studies [i, 2] we showed that in the bodies of white rats phenazepam is hydroxylated with the formation of metabolites containing the hydroxyl group in the 3- position and in the aromatic rings. In the indicated studies, the direction of the aromatic hydroxylation of phenazepam was not established. The purpose of the present investigation was a detailed study of the structure of the metabolites of phenazepam formed in the ...