the chemical composition of the essential oil obtained from the aerial parts of z. clinopodioides subsp. rigida (boiss.) rech. f. was analysed by gc and gc-ms. thirty-one constituents accounting to 99.5% of the total oil were identified. oxygenated monoterpenes (93.3%) were the predominant portion of the oil with pulegone (45.8%), piperitenone (17.4%), p-menth-3-en-8-ol (12.5%) and thymol (8.0%) as the main constituents. antibacterial activity of the oil and its two main compounds and various extracts of plant were tested against seven gram-(+) or gram-(-) bacteria. it was found that the oil and meoh extract (m) exhibited interesting antibacterial activity. the samples were also subjected to screening for their possible antioxidant activity by using 2,2-diphenyl-1-picrazylhydrazyl (dpph) assay. the free radical scavenging activity of meoh extract (m) was superior to all other extracts (ic50=30.7 microg/ml), while the oil was less effective.