Interest in essential oils has generated because of their commercial utility as perfumes and as food favours. However, it is now realized that components of essential oils and their constituents have a considerable range of applications. Various essential oil are biocides against a broad range of organisms such as virus, bacteria, protozoarius, fungi, insects and plants. Others possess pharmacological effects, such as anti-inflammatory, antioxidant and anticarcinogenic. And others exert their activities over the nervous system. This include anxiolitic, sedative, antidepressive and   analgesic  activities. In the present review the main activities of essential oils and its constituents are described.