abstract chemical composition of the essential oil isolated by hydrodistillation from the aerial blooming parts of bidens cernua was analyzed. by gc and gc/ms analysis, 16 components were identified (70.1% of the total oil). the plant material yielded 0.5% (v/w) of gold-yellowish liquid with intensive, unpleasant and heavy scent. the principal compound was identified as 1-phenylhepta-1,3,5-triyne (57.1%), followed by sesquiterpenes caryophyllene oxide, humulene-1,2-epoxide and -selinene (3.0%, 3.1% and 1.1% respectively), as well as (e,e)-1,3,11-tridecatriene-5,7,9-triyne (1.8%).