The FAB (Fast Atom Bombardment)-mass spectrometric ionization technique, which has now been available for about 1 year, has been successfully employed in forensic toxicology. The mass spectral behaviour of some representative drug-glucuronides (Codeine, p-Nitrophenol and 2-Phenyl-1-propanol) were studied by positive- and negative-ion-FAB-MS. The presented promising results may be of some interest, not only for the analytical toxicologist.