From the roots of Aconitum toxicum, acotoxicine (1), a new bisnorditerpene alkaloid, was isolated together with the structurally related delavaconitine, delavaconine, dolaconine, aconosine, and the norditerpene alkaloid neolinine. The structure of compound 1 was elucidated by spectroscopic data interpretation. Further, eight lipo-alkaloids (2-9) were detected in the plant material by LC-APCI-MSn analysis. This is the first report of a C18 bisnorditerpene alkaloid and lipo-alkaloids from A. toxicum.