Abstract The essential oils of three Turkish endemic Heracleum species, H. crenatifolium Boiss., H. platytaenium Boiss. and H. sphondylium L. subsp. ternatum (Velen.) Brummitt were obtained using hydrodistillation (HD), microwave-assisted hydro-distillation (MWHD), microdistillation (MD), micro steam distillation-solid-phase microextraction (MSD-SPME) techniques and analyzed by GC and GC/MS. Compositions of the oils isolated by different methods showed some differences. The main components in all the oils were found to be octyl acetate (19â95%) and octanol (0.6â5.0%). Octyl isovalerate (0.8â6.4%) and decyl acetate (0.5â4.3%) were the next most abundant constituents in the oil of H. crenatifolium. Octyl hexanoate (3.0â4.7%), (Z)-4-octenyl acetate (1.6â2.1%), octanol (0.7â1.0%) and decanal (0.7â1.2%) were the next major constituents in the oil of H. platytaenium. Octyl butyrate (34.6â41.0%), apiole (4.7â20.4%), (Z)-4-octenyl acetate (2.2â4.4%) and (Z)-4-octenyl butyrate (2.6â3.0%) were found as other main constituents in the oil of H. sphondylium subsp. ternatum.