Three new alkaloids, ryosenamine (I), ryosenaminol (II) and ibuki-namine (III), were isolated from Rconitum ibukiense Nakai (ibuki tori-kabuto). The structure of ryosenamine (I) was elucidated as 1-deoxy-hypognavine by spectroscopical study and determined by its correlation. with ryosenaminol (II), the structure of the latter being confirmed by X-ray analysis. The structure of ibukinamine (III) was also determined by X-ray analysis. © 1983, The Pharmaceutical Society of Japan. All rights reserved.