Alkaloids and cytotoxic activity of two samples ofPapaver dubiumsubsp.dubiumand one sample ofP. dubiumsubsp.laevigatumhave been investigated. Berberine (1), thalifendine (2), corydine (3) and isocorydine (4) have been isolated from the first sample ofP. dubiumsubsp.dubium.The second sample of this species yielded berberine (1), thalifendine (2), isocorydine (4), stylopine (5) and tetrahydropseudocoptisine (6) which was isolated for the first time as a natural product. The existence of roemerine (8), mecambrine (9) and allocryptopine (10) has been shown inP. dubiumsubsp.laevigatum.The tertiary extract of the latter showed high cytotoxicity.