Abstract Chemical composition of the essential oils obtained by hydrodistillation of the stems (before and at full flowering stage), unripe and ripe seeds of Heracleum persicum L. were investigated by a combination of GC and GC/MS. Twenty-four components were characterized for the stem oil before flowering with (E)-anethole (47.0%), terpinolene (20.0%), Î³-terpinene (11.6%) and limonene (11.5%) as the main constituents. At full flowering stage, 33 compounds were identified in the stem oil with (E)-anethole (60.2%), terpinolene (11.3%) and Î³-terpinene (7.1%) as the major components. Among the 30 compounds identified in the seed oil of H. persicum, the major constituents were hexyl butyrate (22.5% and 35.5%), octyl acetate (19% and 27%) and hexyl isobutyrate (9.1% and 3.2%) in unripe and ripe seeds, respectively.