By combination of capillary GLC and mass spectrometry it was possible to analyze the composition of the essential oil obtained by steam distillation from leaves and flowers of ARTEMISIA ARBORESCENS L. growing in Sassari (Osilo) in Sardinia. This oil is coloured blue by the presence of relatively high amounts (11.32%) of chamazulene, a substance with anti-inflammatory properties. The oil, after separation in fractions on a silica gel column, was investigated by means of capillary GLC and capillary GLC-MS. Thujone, camphor and chamazulene account for about 75% of the oil. Almost a hundred minor components were found by capillary GLC and 44 were identified.