Abstract The compositions of the essential oil from the aerial parts of Aster ageratoides var. ovatus (Compositae), have been investigated by GC and GC/MS. The volatile components were also isolated by headspace techniques and analyzed. As a result, the oil was revealed the presence of 106 components, representing 97.5% of the total oil. The main components of the oil were bornyl acetate (13.0%), terpinolene (9.7%), bicyclosesquiphellandrene (9.5%), (E)-Î²-ocimene (9.1%) and (Z)âÎ²-ocimene (7.6%). Twenty-one components accounting for 99.6% of the headspace constituents were identified.