SynopsisCrithmum maritimumL. is a halophyte and chasmophyte apiaceous plant, which grows on all the world's coastlines but is particularly abundant in France. The essential oil obtained by steam distillation from samples of leaves ofCrithmum maritimumL. gathered in two areas of France, Brittany and Provence, was analysed first by ultraviolet spectroscopy and secondly by capillary GC.In the first analysis, two distinct UV spectra were obtained depending on the two origins. In all, about 27 components were identified in the two sample types by GC, and they were quantified when possible. Dillapiole is the main constituent representing 75% of the oil whatever its origin.