This chapter discusses Engineering Interventions for Extraction of Essential Oils from Plants. Hydro distillation is used to isolate essential oil from the aromatic plant via boiling water and plants or using steam. Due to the effect of hot water or steam, the essential oils are separated from the oil glands, which are present in the plant tissue. Ohmic heating (Joule heating) is a novel thermal treatment. In this technology, internal heat generates in food via passing of alternative electric current within the food, then food converts to electrical resistance. The specific gravity and reflective index for essential oils was not affected significantly by extraction methods. The prospective future of essential oils distillation depends on the improvement of water distillation and steam distillation methods by using new technologies such as ultrasonic treatments, super-critical fluids especially supercritical CO2, as well as designing systems for distilling essential oils using infrared radiation technology.