The processing of this plant (1) for the four new oncolytic agents, vincaleukoblastine, leurosine, leurosidine, and leurocristine, has resulted in obtaining eight new companion dimeric alkaloids, these latter being obtained in yields of not more than 1.5 × 10−4 %. To date, a total of 24 new alkaloids have been reported from these laboratories. Procedural details and preliminary characterization of carosidine, carosine, pleurosine, neoleurosidine, vincarodine, catharicine, vindolidine, and neoleurocristine are described. Copyright © 1962 Wiley‐Liss, Inc., A Wiley Company