eupatorium cannabinum subsp. corsicum (l.) is an endemic subspecies from the island of corsica. the essential oil from the roots of this aromatic plant has been studied by gc, gc-ms and by 13c-nmr. in contrast to the essential oil from the aerial parts, which is dominated by hydrocarbon compounds (76.9%) and particularly by sesquiterpene components (43.3%), the essential oil from the roots was characterized by a high content of oxygenated compounds (61.0%), particularly oxygenated monoterpenes (54.0%). in the root oil, 106 components were identified representing 96.1% of the total amount. this oil was dominated by the monoterpenes esters (33%), the major components of which were neryl isobutyrate (17.6%), thymyl methyl oxide (15.1%), delta-2-carene (14.5%) and beta-pinene (5.7%). aromatic esters, nerol derivatives (esters and diesters) and a benzofuran were investigated by gc-ms using different ionization modes including electron impact ionization, and positive- and negative-chemical ionization. these components have not previously been reported in the essential oil of aerial parts of e. cannabinum from corsica island.