abstract the essential oil of eryngium foetidum leaves from s. tom'e e pr'incipe was investigated for the first time. the oils were obtained by hydrodistillation of the leaves, from two different sites, and subsequently analyzed by gc, gc/ms and 13c-nmr. the oils were characterized by the presence of small amounts of monoterpene hydrocarbons and sesquiterpenoids, and by a large number of aromatic and linear aldehydes in high proportions, with 2,3,6-trimethylbenzaldehyde (5.5-23.7%), (e)-2-dodecenal (15.9-37.5%) and (e)-2-tetradecenal (18.7-25.3%) being the most dominant.