Pesticides are substances or mixtures of substances used primarily in agriculture or in public health conservation programs to protect plants from pests, weeds or diseases and to protect humans from vector-borne diseases such as intestinal sickness, dengue fever and schistosomiasis. Pesticides, fungicides, herbicides, rodenticides and plant growth regulators are typical examples. These products are also used for other purposes such as development and maintenance of non-agricultural areas such as public urban green areas and sports fields. Furthermore, there are other lesser-known applications of these chemicals in pet shampoos, building materials, and boat bottoms to eliminate or prevent the presence of unwanted species.

Many pesticides have been linked to health and environmental problems, and agricultural use of some pesticides has been abandoned. Presentation to pesticides can be through skin contact, ingestion or inward breath. The type of pesticide, duration and route of exposure, and individual health status (eg, nutritional deficiencies and healthy/damaged skin) are factors in possible health outcomes. In the human or animal body, pesticides may be metabolized, excreted, stored, or bioaccumulated in body fat. Many of the adverse health effects associated with chemical pesticides include, among others, cutaneous, gastrointestinal, neurological, carcinogenic, respiratory, reproductive, and endocrine effects. Moreover, excessive occupational, accidental or intentional exposure to pesticides can lead to hospitalization and death.