Abstract The oils obtained by hydrodistillation and the headspace volatiles from the aerial parts of Bombycilaena erecta and Otanthus maritimus were analyzed by means of GC and GC/MS. The major components of the oils of Otanthus maritimus were cis-chrysanthenyl acetate (30.4%); camphor (12.9%) and artemisia alcohol (12.6%), while those of Bombycilaena erecta were camphor (18.8%); yomogi alcohol (14.9%) and artemisyl acetate (9.1%). Additionally, the repellency of the investigated species against the ant Monomorius pharaonis was studied.