The nitrosatability of Pryleugan (imipramine), Herphonal (trimipramine), and Finlepsin (carbamazepine) was investigated under simulated human gastric conditions using a colorimetric measuring method. All of them proved to be nitrosatable even at very low nitrite concentrations. In the presence of ascorbic acid, the formation of N-nitroso compounds under model conditions was inhibited markedly. N-nitroso-dihydrodibenzazepine and N-nitroso-dibenzazepine could be identified by thin layer chromatography as main products. The biological effects of these N-nitroso compounds are not known up to now.