The essential oils contained in aromatic and medicinal oils give off fragrance that could equal the benefits of conventional pharmaceutical medications. They are used in different fields such as: cosmetic, food industry, and herbal medicine. During this lecture, Mrs Bouzouita Nabiha, Assistant lecturer at the Ecole Supérieure des Industrie Alimentaires of Tunis (ESIAT), informed us about these oils and the fields of their applications.