Two aromatic species from the Atacama people traditional medicine, Aloysia deserticola (Phil.) Lu-Irving & OâLeary and Artemisia copa Phil. var. copa, from Antofagasta area (North of Chile) were investigated for their essential oils (EO) chemical composition, antioxidant and antimicrobial activity. EO of A deserticola collected in four different spots unexpectedly contained Î±-thujone as the major compound instead of the Î²-isomer described for other Chilean and Bolivian specimens in the literature. For EO of Artemisia copa var. copa, chrysanthenone was the main compound whereas Î²-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. deserticola essential oil.