Synthetic pyrethroid insecticides had been widely used (in agriculture, home pest control and disease vector control) for their high activity as an insecticide and low mammalian toxicity. This low mammalian toxicity was due, in part, to their rapid metabolism in these animals (Dick et al., 1984). Pyrethroids had been subdivided into two classes based on their structural characteristics and pharmacological effects. Type I pyrethroids such as allethrin and permethrin do not contain c-cyano group, which is present in type II pyrethroids such as deltamethrin, cypermethrin and fenvalerate (Moya-Quiles et aI., 1996). The lipophilia of pyrethroids favored their absorption through the skin, gastrointestinal and respiratory tracts to be more distributed into lipid-rich internal tissues, including body fat and elements of the central and peripheral nervous system (Soderlund et aI., 2002).