The compositional variability of the essential oils of aerial parts of mugwort (Artemisia vulgaris L.), collected from fifteen wild populations in Lithuania is detailed. The most predominant components were davanones (13.8-45.5%, six oils), germacrene D (9.1-30.5%, four oils), 1,8-cineole (16.4%, one oil), camphor (18.9%, one oil), trans-thujone (8.9 and 10.9%, two oils) and cis-chrysanthenyl acetate (10.4%, one oil). To the best of our knowledge, the davanone chemotype for A. vulgaris oils is described for the first time. The toxicity of the mugwort essential oils was determined using brine shrimp (Anemia sp.) assay. LC0 values (10.3-23.1 μg/mL) obtained for the oils after 24 h of exposure revealed that the oils containing appreciable amounts of germacrene D, 1,8-cineole, camphor and davanone were notably toxic.