The structures of five new C20-diterpene alkaloids having the napelline skeleton, i.e., 12-epi-lucidusculine (2), 12-epi-19-dehydronapelline (8), 12-epi-19-dehydrolucidusculine (9), liangshanine (3), and liangshanone (11), found from the roots of Aconitum liangshanium, were determined by spectroscopic analysis and chemical reactions. © 1991, The Pharmaceutical Society of Japan. All rights reserved.