Abstract The chemical composition of the leaf oils of Pluchea carolinensis Jacq. and Ambrosia hispida Pursh. were studied by GC and GC/MS. One hundred and thirteen compounds of the oil of P. carolinensis were identified of which juniper camphor (37.6%) was the major component. In the oil of Ambrosia hispida, 84 were identified of which borneol (19.4%) and spathulenol (11.8%) were the major components. Key Word Index: Pluchea carolinensis Ambrosia hispida Asteraceaeessential oil compositionjuniper camphorborneolspathulenol