Branch of toxicology deals with insecticides. Most of the insecticides enter through skin. Some of the insecticides are volatile and enter through inhalation into the body. This branch also deals with safety, degradation and refinement of insecticides in environment. Laboratory investigations provide a better understanding of insect- insecticide or insect-plant-insecticide-soil interactions. Insecticides are substances used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by consumers.