Qualitative and quantitative variations in the diterpene alkaloids content in the neomontanum subspecies of Aconitum napellus, growing near lake of Como, were studied throughout its complete onthogenetic cycle. Aconitine, N-deethylaconitine and two compounds with m.w.- 688 and m.w. = 629 have been detected in the various organs of plant almost at any time during the vegetative cycle. © 1988, The Italian Pharmacological Society. All rights reserved.