It is a generic term to define the chemicals that are used to kill or eradicate pests of any environment (home, crops, human body, livestock, etc.) ) . There are in different forms such as liquids, baits, wettable powders, pills or tablets, creams or shampoos. They can be garrapaticidas, nematicides, rodenticides, fungicides, etc. They are products that should be handled with care given its high toxicity, many are carcinogenic, teratogenic, have residual and mortals. Plague called an animal that proliferates and affects crops or production, animal or human health.