From the ethanol extract of the stems of Aristolochia manshuriensis, two new alkaloids, namely manshurienine A (1) and manshurienine B (2), were isolated together with six known compounds, i.e., aristoloside (3), aristolochic acid I (4), aristolochic acid II (5), aristolic acid II (6), aristolochic acid IVa (7), and aristolochic acid IIIa (8). The structures of 1 and 2 were elucidated on the basis of spectroscopic methods, mainly by using 1H-and 13C-NMR spectroscopy, and the known compounds 3-8 were identified by comparing their physical and spectroscopic data with those of authentic data reported in the literature. © 2006 Verlag Helvetica Chimica Acta AG.