From the roots of the previously unstudied species Aconitum umbrosum collected in the flowering period in the environs of Utkura (Sikhot6-Alin' range) we have isolated lycaconitine, anthranoyllycaconitine, ajacine, and a new base with the composition C24H39NO6, mol. wt. 437.2738, mp 150-151°C (hexane), which we have called umbrosine (I). According to its NMR spectrum (CDC13, δ scale), the alkaloid contains a methyl group (1.05 ppm, 3H, triplet) and three methoxy groups (3.33, 3.28, and 3.26 ppm, 3H each). Its composition and spectral characteristics permit the conclusion that umbrosine is based on a lycoctonine skeleton, and the subsequent chemical reactions of (I) confirmed this hypothesis.