AbstractTetrahydroisoquinoline alkaloids, which are known to be present not only in plants but also in animals, including mammals, can be considered as condensation products of 2‐phenylethylamines (e.g., catecholamines) with aldehydes (e.g., acetaldehyde) or 2‐oxo acids (e.g., pyruvic acid). In this study the possibility of separating the optical isomers of several tetrahydroisoquinolines by high‐performance liquid chromatography was investigated. For isosalsoline, tetrahydropapaveroline and laudanosoline a good enantiomeric separation could be achieved by applying β‐cyclodextrin‐bonded silica as stationary phase in connection with various mobile phases. With respect to laudanosoline, the addition of β‐cyclodextrin as chiral selector to the mobile phase using a C18reversed‐phase column as stationary phase revealed an even higher resolution when compared with the chiral columns. All tested tetrahydroisoquinolines which could be well separated into enantiomers bear a hydroxyl group at carbon atom 7 as a common structural feature. Those alkaloids substituted with a methoxy group on position 7 instead of a hydroxyl group (e.g., salsolidine) failed to be resolved into their optical isomers. Therefore, the presence of a hydroxyl group on C7 of the aromatic ring seems to be conducive to steric discrimination. However, the separation results for 1‐carboxysalsolinol were unsatisfactory although this molecule possesses a 7‐hydroxyl group. In this case the existence of a carboxyl group on C1 reduced the chiral recognition and thus the enantiomeric resolution. ©