essential oils from five wild species growing in lebanon and used in traditional medicine were obtained by hydrodistillation. their chemical composition was determined by gas chromatography (gc) and gc-mass spectrometry (gc-ms), and the major constituents were -pinene in juniperus excelsa m. bieb. (68.8-86.8%, according to different organs), carvacrol in thymbra spicata l. (65.8%) and coridothymus capitatus (l.) rchb. f. (47%), pulegone in mentha spicata l. subsp. condensata (briq.) greuter & burdet (32.8%) and 1,8-cineole in salvia fruticosa (mill.) k. schum. (48.7%). antiradical capacity of the essential oils was measured in vitro by the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (abts.+) radical cation and 2,2-diphenyl-picryl hydrazyl (dpph.) radical assays. a good agreement between the two tests was recorded: c. capitatus and t. spicata oils showed the highest abts.+ and dpph. radical-scavenging activity, possibly due to their high levels of carvacrol, whereas the lowest antiradical capacity was reported for j. excelsa oils.