Three new diterpenoid alkaloids, namely 1-N-deethyl-1,16-demethoxy-1,16-dihydroxy-N(19)-enaustroconitine A (1), 1-N-deethyl-1,16-demethoxy-1,16-dihydroxy-18-methoxy-N(19)-en-austroconitine A (2), and 1-N-deethyl-1,16-demethoxy-1,16-dihydroxyranaconidine (3), were isolated from the 80% ethanol extract of the roots of Aconitum iochanicum. Structural elucidation of all the compounds was performed by spectral methods such as 1D and 2D (1H–1H COSY, HMQC, and HMBC) NMR spectroscopy, in addition to high-resolution mass spectrometry. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.