the essential oil (eo) composition of ripe fruit of s. terebinthifolius raddi was analyzed by gc-ms. the oil extraction yielded 6.54 +/- 1.06% (w/w). seventeen compounds were identified, accounting for 91.15% of the total oil, where monoterpenes constituted the main chemical class (85.81%), followed by sesquiterpenes (5.34%). the major monoterpene identified was -3-carene (30.37%), followed by limonene (17.44%), -phellandrene (12.60%) and -pinene (12.59%). trans-caryophyllene (1.77%) was the major sesquiterpene identified. the antibacterial activity of the essential oil was evaluated against wild strains of hospital origin (escherichia coli, pseudomonas sp., klebsiella oxytoca, corynebacterium sp., staphylococcus aureus, enterobacter sp., enterobacter agglomerans, bacillus sp., nocardia sp. and streptococcus group d). the essential oil of the ripe fruit of s. terebinthifolius raddi has shown to be active against all tested wild strains, with minimum inhibitory concentration ranging from 3.55 g/ml to 56.86 g/ml. however, it has revealed some differences in susceptibility: the general, gram-positive species showed greater sensitivity to the action of eo, which is probably due to the lower structural complexity of their cell walls.