The use of herbs and plants in food industry has a long history.The diversity among the components of the plants has resulted in their use in many applications including in flavors as well as in medicine.The conventional method for the extraction of essential oils are is hydrodistillation (HD),soxhlet in which the essential oils are evaporated by heating a mixture of water and plant materials followed by the liquefaction of the vapors in a condenser. This method suffers from several disadvantages including losses in the volatile compounds,long extraction time and degradation of some components through thermal process. Microwave heating has an incontestable place in analytical and organic laboratory practices as a very effective and non-polluting method of activation.In this book,microwave-assisted hydrodistillation (MAHD) was used to extract an essential oil from the Ginger,and Limon grass. Then results compared with the conventional hydrodistillation method.The MAHD resulted in a shorter extraction time compared to the Hydrodistillation (HD),the extraction yield obtained by MAHD is slightly higher than that from HD.And microwave power is very efficient in the extraction.