Chemical investigation of aerial parts of Thalictrum minus, collected at two localities of Vojvodina, showed the presence of dimers of the bisbenzylisoquinoline type (thalmethine, O-methylthalmethine, thalicberine and O-methylthalicberine) and monomers of the isoquinoline type (thaliglucine, thaliporphine, berberine, thalactamine and thalflavine). On the basis of the structure of the major alkaloids, the populations were divided into two chemotypes. The plants were found to be hexaploids. © 1992.