Abstract The hydrodistilled oil from the fresh and dried aerial parts of Tessaria absinthioides was analyzed by a combination of GC and GC/MS. Thirty-three compounds representing 85% of the oil were identified. The main components of the oil were caryophyllene oxide (12.2%), (E)-Î²-damascenone (8.6%) and Î³-eudesmol (8.5%). The oil consisted of about 32% oxygenated monoterpenes, 36% oxygenated sesquiterpenes and 17% sesquiterpene hydrocarbons. The ratio of oxygenated monoterpenes to oxygenated sesquiterpenes changed from 4.8 to 0.9 in oil of air-dried versus oil of fresh material