A chemical investigation of the 80% ethanol extract of the roots of Aconitum episcopale led to the isolation of two undescribed C19-diterpenoid alkaloids, designated as episcopines A and B. The structures of the new compounds were elucidated by spectroscopic analysis (NMR, IR, UV, and MS). The isolated alkaloids were tested in vivo for antinociceptive potential. Episcopine A showed a 2-fold more potent antinociceptive effect (ID50 = 66.1 μmol/kg) than the positive control drugs aspirin and acetaminophen. © 2021, Springer Science+Business Media, LLC, part of Springer Nature.