The structure of racemulosine (1), a novel skeletal C-20-diterpenoid alkaloid isolated from Aconitum racemulosum Franch var. pengzhouense, was confirmed on the basis of spectroscopic data including 2D NMR (HMQC, H-1 COSY, HMBC, NOESY) and especially X-ray crystallographic analysis. (C) 2000 Elsevier Science Ltd. All rights reserved.