The structures of three unstable amides from the roots of Asiasarum heterotropoides MAEK. var. mandshuricum MAEK. (Aristolochiaceae) were established as (2E,4E)-N-isobutyl-2,4-decadienamide (pellitorine), (2E, 4E, 8Z, 10E)-N-isobutyl-2,4,8,10-dodecatetraenamide and (2E, 4E, 8Z, 10Z)-N-isobutyl-2,4,8,10-dodecatetraenamide by spectroscopic investigation and chemical transformation studies. (2E, 4E, 8Z, 10E)-N-Isobutyl-2,4,8,10-dodecatetraenamide and (2E, 4E, 8Z, 10Z)-N-isobutyl-2,4,8,10-dodecatetraenamide were identical in their chromatographic properties, but they could be identified in a mixture of both compounds by our carbon-13 nuclear magnetic resonance method, by observing the cis double bond shielding effect in comparison with the all-trans isomer.