Abstract The water distilled oils from the aerial parts of Ducrosia assadii Alava., endemic in Iran, and Prangos acaulis (DC.) Bornm. were analyzed by GC and GC/MS. Decanal (36.4%) was the main components among the 29 constituents characterized in the oil of D. assadii, representing 88.3% of the total components detected. Twenty-three compounds were identifed in the oil of P. acaulis, representing 90.0% of the total oil, with cis-sesquisabinene hydrate (25.6%) and Î±-pinene (12.5%) as main constituents.