Abstract The composition, the seasonal variations and antimicrobial activity of the essential oil of the aerial parts of Crithmum maritimum growing in Liguria (Italy) was evaluated. The main constituent of the essential oil was always Î³-terpinene (41-68%); sabinene was present in high amount only during fruit ripening (30%), while dillapiole reached its maximum value in December (10%). The oil, tested against some bacteria and mycetes, was effective only towards Candida albicans, Bacillus subtilis and Listeria monocytogenes. The same kind of activity was shown by two of the main compounds, sabinene and methyl thymol.