Abstract: Reptiles are treated to eradicate or to prevent an infestation of ectoparasites, by applying a formulation having a substantially non-volatile active ingredient that is toxic to ectoparasites but generally benign to a reptile to be treated, on an inside surface of a container, and confining the reptile inside the container. In one embodiment, a substrate is placed in the container on which substrate the reptile rests when confined, and the formulation is applied on the substrate. The treatment is particularly suitable for snakes. Permethrin may form the active ingredient of the formulation. The treatment has residual benefits over an extended period of time.