ABSTRACTTwo aromatic species from the Atacama people traditional medicine, Aloysia deserticola(Phil.) Lu-Irving & O’Leary and Artemisia copaPhil. var. copa, from Antofagasta area (North of Chile) were investigated for their essential oils (EO) chemical composition, antioxidant and antimicrobial activity. EO of A deserticolacollected in four different spots unexpectedly contained α-thujone as the major compound instead of the β-isomer described for other Chilean and Bolivian specimens in the literature. For EO of Artemisia copavar. copa, chrysanthenone was the main compound whereas β-thujone was identified in a Bolivian specimen. These EO exerted no significant antibacterial activity on a panel of forty-four strains, whereas notable inhibition of xanthine oxidase activity was observed with A. deserticolaessential oil.