Toxicity tests of wild wormwood essential oils were performed using the brine shrimp (Artemia sp.) test. N auplii lethality (LC 50) ranged 15.7-31.9 µg/mL, depending on oil composition. The most toxic A. absinthium oils were found to be those containing appreciable amount of trans-sabinyl acetate (45.2%) and (cis+trans) thujones (12.3%), while other samples with equivalent amounts of sabinyl acetate, but without thujones were determined to be notably less toxic. Herb material for the tests was collected in Lithuania, the volatile oils were obtained by hydrodistillation from different plant organs (inflorescences and leaves) and analysed by GC-MS