Insecticide synergists are compounds which, although having no direct toxic effect per se at the dosage employed, are able to substantially enhance the observed toxicity of an insecticide with which they are combined. It is now generally recognized that synergists are able to produce their effect by inhibiting the enzymes within the insect responsible for the detoxification of the insecticide. Since most cases of resistance to insecticides are directly related to the increased ability of the insect to metabolize the insecticide, it is obvious that synergists constitute a group of compounds with considerable potential for the control of resistant strains of insects.