From the roots of Aconitum cochleare Woroschin, collected in Turkey, a new diterpenoid alkaloid named acochlearine has been isolated along with the known diterpenoid alkaloids talatisamine, 14-O-acetyltalatisamine, senbusine C and condelphine. The structure for acochlearine was established on the basis of H-1, C-13, DEPT, homonuclear H-1 COSY, NOESY, HSQC and HMBC NMR studies.