A new alkaloid, phygrine, isolated from the roots and aerial parts of Physalis alkekengi has been shown to be bis-hygrine or 1-[1'-methylpyrrolidine-2'-yl]-3-[1-methyl-2-(2'-oxopropyl)pyrrolidine-5-yl]propan-2-one. The alkaloid is also present in P. angulata, P. philadelphica, P. ixocarpa, P. edulis, P. peruviana, P. minima, P. pubescens, P. viscosa and P. pruinosa.