a reversed-phase high-performance liquid chromatographic method was developed for the simultaneous quantitation of the alkaloids of Papaver species in section Oxytona: salutaridine, thebaine, oripavine, alpinigenine, isothebaine and orientalidine. The concentrations of the alkaloids were compared in roots and capsules of the species P. bracteatum, P. orientale and P. pseudo-orientale and their interspecific hybrids. The alkaloid spectrum was similar for the two parts of each plant, and significant correlations were found between the concentration of each alkaloid in the roots and in the capsules. The importance of the results for the screening of plant populations and for breeding purposes is discussed.