The 16 species of the Sedum acre-group were investigated for the presence of alkaloids. They are S. acre of S. ser. Acria, S. alpestre, S. annuum, S. apoleipon, S. borissovae, S. euxinum, S. grisebachii, S. laconicum, S. multiceps, S. sexangulare, S. tuberiferum, S. tuberosum, S. ursi, and S. urvillei of S. ser. Alpestria, S. samium of S. ser. Samia, and S. litoreum of S. ser. Litorea. S. acre differs significantly from the other species. It contains sedamine, "hydroxy" sedamine, and a number of 2,6-disubstituted piperidine alkaloids. The leafy parts of the species of S. ser. Alpestria, S. ser. Samia, and S. ser. Litorea contain 4 piperidine alkaloids which also occur in S. acre, and in addition 4 pyrrolidine alkaloids not present in S. acre. The composition of the alkaloid fraction agrees with the infrageneric classification (series) based on the hybridization patterns of the species (comparia). © 1993 Springer-Verlag.