After oral application of pentacozine (Fortral) besides the unchanged drug some further excretion products were detected by glc/ms in human urine. For their identification e.i.-and c.i.-mass-spectrometry as well as the just recently available FAB-technique were employed. All analyses were performed on a VG-Micromass 7035; the samples were introduced in the ion source via a fused silica, bonded phase capillary column (30 metres; DB-1 J + W, Inc.). The analytical profiles of the pure substance and some metabolites are reported as well as the behaviour of the pure substance on acidic hydrolyzation.