abstract abstract the wild achillea millefolium l. with white, pink and deep pink flowers were collected from the same locality. essential oils were produced by hydrodistillation and analyzed by gc and gc/ms. the main constituents of the inflorescence oils were -pinene (13.1-19.3%), (e)-nerolidol (7.0-16.1%), piperitone (10.8%, deep pink inflorescences), -eudesmol (8.4%, white), -caryophyllene (6.7%, pink) and these of leaf oils--eudesmol (12.8%, white flowering plant), borneol (10.7%, pink), piperitone (10.0%, deep pink), caryophyllene oxide (6.4-10.4%), selin-11-en-4a-ol (6.5-7.5%) and spathulenol (6.1%, pink). the amounts of -pinene decreased and (e)-nerolidol increased in the inflorescence oils with intensity of yarrow fl owers color. the inflorescences with different colored flowers produced markedly higher amounts of sabinene, -pinene, 1,8-cineole, -terpinene, -caryophyllene, -humulene and (e)-nerolidol than leaves. the above correlation was identified for mono- and sesquiterpene hydrocarbons. an opposite correlation was determined for spathulenol, caryophyllene oxide, -eudesmol, selin-11-en-4-ol and oxygenated sesquiterpenes. fifty-two identified compounds made up 93.0-96.6% of the inflorescence oils and 69.2-74.1% of leaf oils. key word index: achillea millefolium asteraceaeessential oil composition-pineneborneolpiperitone(e)-nerolidolcaryophyllene oxide-eudesmol