Phytochemical investigation of Lagotis yunnanensis led to the isolation and identification of a new iridoid glucoside 1, named as 10-O-(3,4-dimethoxy-(E)-cinnamoyl)aucubin. Its structure was elucidated by spectroscopie methods. Phytochemical investigation of Lagotis yunnanensis led to the isolation of identification of a new iridoid glucoside 1, named as 10-O- (3,4-dimethoxy- (E) -cinnamoyl) aucubin. Its structure was elucidated by spectroscopie methods.