The structures of three new C19 diterpenoid alkaloids, flavaconidine (1), N-acetylflavaconitine (2), and flavaconijine (3), isolated in the continuing investigation of Aconitum flavum Hand-Mazz, were determined on the basis of spectroscopic evidence and chemical correlations. They are the first examples of natural diterpenoid alkaloids bearing an acyl instead of usual alkyl group on the nitrogen. © 1989.