summarizes the studies that have used traditional methods for extraction of essential oil from D. kotschyi Boiss and reported extraction yield. The methods include: hydrodistillation, steam distillation and solvent extraction. These techniques are not suitable for volatile components and, as shown in Table 8, require long extraction time. The optimized extraction yield in this study by supercritical fluid technology was 2.72%, which is greater than two times of maximum yield reported in the literature (1.1%). This can be a worthwhile achievement in the essential oil extraction from this valuable medicinal plant.