Aconitum species accumulate highly toxic diterpene alkaloids, which have attracted considerable interest because of their complex structure, interesting chemistry and noteworthy physiological effects. The authors carried out phytochemical analysis of two Aconitum species native to the Carpathian Basin, aiming the isolation of diterpene alkaloids. The multistep chromatographic purification of the extracts of A. vulparia whole plant and A. toxicum root resulted in the isolation of 16 alkaloids. Structure elucidation by means of spectroscopic investigations revealed the presence of 3 (acovulparine, vulparine, acotoxinine) new and 13 already known compounds (anthranoyllycoctonine, delectinine, delcosine, finetiadine, lycoctonine, N-methyl-N-deethyllycocotine, septentriodine, aconitine, aconosine, dolaconine, neoline, songorine, songo-ramine). Alkaloids isolated from A. vulparia are C19 diterpene alkaloids possessing aconitane skeleton, whilst from A. toxicum two C20 diterpene alkaloids with napelline and five diterpene alkaloids with aconitane skeleton were identified. The pharmacological testing of the majority of the isolated compounds has not been reported in the literature yet. Since some of the diterpene alkaloids are structurally very similar to compounds which were active in different in vitro or in vivo experiments, the pharmacological testing of the alkaloids reported in this article seems to be reasonable. The investigation of the compounds may help to reveal structure-activity relationships as well.