A new norditerpenoid alkaloid, 1-epi-deacetylaconitine (1), along with three known compounds, neoline, songorine and 12-epi-napelline, was isolated from the roots of Aconitum nemorum. The structure of the new compound was elucidated on the basis of 1D and 2D NMR, EIMS and FABMS experiments. The structure of 1-epi-deacetylaconitine is unusual because it is the only aconitine series norditerpenoid alkaloid in which the I-methoxyl group exists in the beta -configuration and an intramolecular hydrogen bond is present between the nitrogen atom and the hydrogen of 3 alpha -hydroxyl group.