Essential oil extracted from fresh aerial parts of Athamanta sicula L. (syn. Tingara sicula) was analysed by gas phase chomatography coupled to mass spectrometry (GC-MS). The main constituents were: germacrene B (88.5%) and apiol (4.9%). Comparing with the tested bacteria, the growth of Escherichia coli and Klebsiella pneumoniae strains was more inhibited by the essential oil of A. sicula.