A rare arcutine-type C_(20)-diterpenoid alkaloid, named aconicarmicharcutinium A and obtained as hydroxide(1) and trifluoroacetate(1a), was characterized as a minor constituent of “fu zi”(the lateral roots of Aconitum carmichaelii). The structures of 1 and 1a were elucidated by comprehensive analysis of spectroscopic data including~(19)F and 2D NMR experiments. Compounds 1 and 1a represent the first examples of the arcutine-type C_(20)-diterpenoid alkaloid iminium. A rare arcutine-type C 20 (20) -diterpenoid alkaloids, named aconicarmicharcutinium A and obtained as hydroxide (1) and trifluoroacetate (1a), was characterized as a minor constituent of “fu zi ” (the lateral roots of Aconitum carmichaelii) . The structures of 1 and 1a were elucidated by comprehensive analysis of spectroscopic data including ~ (19) F and 2D NMR experiments. Compounds 1 and 1a represent the first examples of the arcutine-type C_ (20) -diterpenoid alkaloid iminium.