Catalyzes the oxidative metabolism of numerous xenobiotics, including mainly therapeutic drugs and insecticides that contain a soft nucleophile, most commonly nitrogen and sulfur and participates to their bioactivation. H(+) + N,N-dimethylaniline + NADPH + O2 = H2O + N,N-dimethylaniline N-oxide + NADP(+) Belongs to the FMO family.