The essential oils from leaves of Verbesina diversifolia DC., at different ontogenetic stages, were obtained by hydrodistilation and analysed by GC–FID and GC–MS. The oils were mainly (56.7–75.7%) constituted by sesquiterpenes; 82.6–94.1% of the chemical composition of the essential oils of plants at the flowering stage were identified, with β-caryophyllene (7.4–14.8%), bicyclogermacrene (21.7–23.2%) and germacrene D-4-ol (14.1%) as the major constituents. In the essential oil of plants at the vegetative stage, 18 constituents, corresponding to 96.2% of the chemical composition, were characterized, bicyclogermacrene (20.7%), germacrene D (14.3%), germacrene D-4-ol (10.9%) and β-caryophyllene (10.7%) being the chief compounds. Copyright © 2006 John Wiley & Sons, Ltd.