abstract essential oils isolated by hydrodistillation from the aerial parts of tanacetum polycephalum schultz-bip. subsp. argyrophyllum (k. koch.) podlech before flowering and at full flowering stage, were analyzed by a combination of capillary gc and gc/ms. twenty-five components were identified that approximately constitute 92.8% and 97.9% of the oils, before flowering and full flowering stage, respectively. the main constituents of the oils were camphor (36.1% and 18.5%), pinocarvone (20.1% and 31.4%), -pinene (8.6% and 9.5%), p-cymene (9.2% and 0.5%) and bornyl acetate (8.8% and 5.9%) before flowering and full flowering stage, respectively. 1,8-cineole (18.5%) was found only in the oil of full flowering. there were some other differences between the minor components of the oils in two harvesting time.