<jats:p><jats:italic>Papaver rhoeas</jats:italic> var. <jats:italic>chelidonioides</jats:italic> O. KUNTZE (diploid, 2<jats:italic>n</jats:italic> = 14) contains rhoeadine (0.027%) and coptisine (0.004%) as the dominant alkaloids, the latter being the yellow principle of the latex. As minor constituents were isolated protopine, papaverrubine A, rhoeagenine, (-)-stylopine, an unidentified alkaloid PCH 1 (m.p. 205 °C), 2-methyl-1,2,3,4-tetrahydro-β-carboline and (-)-<jats:italic>trans</jats:italic>-N-methylstylopinium hydroxide. Chromatographic analysis detected isorhoeadine, allocryptopine, cryptopine, papaverrubine C, D and E, scoulerine, isoboldine, berberine, corysamine, magnoflorine and corytuberine. <jats:italic>P. confine</jats:italic> JORD. (tetraploid, 2<jats:italic>n</jats:italic> = 28) was found to display a very low alkaloid content (0.003%) and afforded corytuberine and berberine as principal alkaloids, along with minor amounts of protopine rhoeadine, scoulerine and cryptopine. Chromatography identified isocorydine, corydine, allocryptopine, aporheine, stylopine, sinactine, thebaine, mecambrine, papaverrubines A, E, C and D, coptisine and corysamine. The tertiary alkaloid fraction from ripe capsules of <jats:italic>P. dubium</jats:italic> L. (hexaploid, 2<jats:italic>n</jats:italic> = 42; 0.24% of alkaloids) of domestic origin afforded (+)-roemerine (aporheine) as the main constituent (87% of total bases); mecambrine, protopine, rhoeadine and papaverrubines D and C (traces of A and E) were detected. From strongly polar bases N-methylaporheinium hydroxide (as iodide) was isolated and corytuberine detected.