© 2019 IEEE.Repellent is a general title for the substance which removes insects from human and domestic animals. Repellent substances are used for blood-sucking and disturbing insects in close and open areas. Repellent substances are extremely useful in the struggle with insects. However, especially synthetic insect repellents are toxin for human and animals. In this study, identification of repellents, mechanism of action, properties of repellents and repellent natural oils are investigated.