the essential oils of hertia cheirifolia, collected from different bioclimatic zones of tunisia, were analyzed by gc-ms and gc-fid. the major compounds were -pinene (17.51-60.31%), germacrene d (6.14-19.18%), unknown drimenin isomer (9.39-32.39%) and drimenin (0.46-33.61%). the essential oil composition varied significantly between populations. the chemical differentiation among populations occurs regardless their eco-geographic appurtenances. the species essential oils exhibited antioxidant and antiacetylcholinesterase activities. however, the level of activity varied between populations. the highest scavenging activity characterized the essential oils of the species collected from sousse and zaghouan (22.26 and 21.35 mg te/geo). essential oils from sousse possessed the uppermost inhibition of -carotene bleaching (37.82 mg bht equivalent/geo). essential oils from sousse and makthar exhibited the highest reducing capacity (162.05 and 171.80 umol fe2+/geo). essential oils from siliana possessed the highest chelating ability (17.55 mg edta equivalent/geo). those from siliana and sousse exhibited the highest antiacetylcholinesterase activity (3.03 and 2.91 mg donepezil/geo).