Essential oils as odorous and volatile compounds are found only in 10% of the plant kingdom. They are stored in medicinal and aromatic plants in special brittle secretory structures. They are hydrophobic and alcohol soluble (slightly soluble in water) waxes and oils. Most of them are liquid and colorless or pale yellow except for the blue essential oil of chamomile (Matricaria recutita L.). Since ancient times, essential oils are recognized for their medicinal value. They can be acquired in an industrial scale for various industries and purposes as perfumes, flavoring foods and beverages. The cultivation of medicinal plants in their original habitat leads to the production of essential oil with the highest quality and quantity. Due to the existence of special species of medicinal herbs and also particular climate conditions, Iran has the excellent potential of representing the highest quality of essential oils according to required quantity of the customers need.