Two new quaternary protoberberines, thalifaurine and dehydrodiscretine, were isolated from the ethanolic extract of Thalictrum fauriei Hayata. Based on spectral analysis and correlation with compounds of known structure, thalifaurine was shown to be 3‐hydroxy‐2‐methoxy‐10,11‐methylenedioxyberbinium chloride and dehydrodiscretine was established as 3‐hydroxy‐2,10,11‐trimethoxyberbinium chloride. The structural assignment was confirmed by synthesis of both compounds. Magnoflorine also was isolated and identified. Copyright © 1980 Wiley‐Liss, Inc., A Wiley Company