The new C20-diterpene alkaloid acoridine has been isolated from the epigeal part of Aconitum coreanum (Levl.) Rapaics, and the structure of 14-hydroxy-2-propionylhetisine has been established for it on the basis of spectral characteristics. Acoridine is the first diterpene alkaloid esterified by propionic acid. © 1991 Plenum Publishing Corporation.