From leaves of PENSTEMON SERRULATUS Menz. two new iridoid glycosides have been isolated. Both glycosides have the same aglycon part, but differ in their carbohydrate moieties. The structure of serru-loside (penstemidaglucon-11- O-beta- D-ribohexos -3-uloside) and serrulatoside (penstemidaglucon-ll-