New alkaloids, (+)-triniifoline, (+)-O-ethyltriniifoline (rhoeadine type), and (+)-miltanthaline (benzylisoquinoline type) have been isolated from aerial parts of Papaver triniifolium Boiss, (Papaveraceae). The major alkaloids were medicinally important (-)-alpha-narcotine and papaverine together with (-)-mecambrine in the species whereas narceine and (-)-N-methylcrotonosine were minor alkaloids. The known (-)-alpha-narcotine, narceine and (-)-N-methylcrotonosine have been isolated for the first time from P. triniifolium.