The isoquinoline alkaloids protopine, cryptopine, sinactine, stylopine, bicuculline, adlumine, parfumine, fumariline, fumarophycine, fumaritine, dihydrofumariline, parfumidine and dihydrosanguinarine have been determined and identified by gas chromatography-mass spectrometry in Fumaria agraria, F. bastardii, F. capreolata, F. sepium, F. densiflora, F. faurei, F. officinalis subsp. officinalis, F. parviflora, F. petteri subsp. calcarata and F. macrosepala. The chemotaxonomic significance of the results is discussed.