Disclosed is a method of controlling ectoparasites that infest companion and livestock animals by applying to the animal an effective amount of 4-tert-butylphenethyl quinazolin-4-yl ether or 4-chloro-5-ethyl-2-methyl-N-[(4-tert-butylphenyl)methyl]pyrazol e-3-carboxamide or 5-chloro-N-[2-[4-(2-ethoxyethyl)-2,3-dimethylphenoxy]ethyl]-6-e thyl-4-pyrimidinamine or 4-chloro-3-ethyl-1-methyl -N-[4-(p-tolyloxy)benzyl]pyrazole-5-carboxamide.Se divulga un método para controlar ectoparásitos que infestan animales de compañía y ganado al aplicar al animal una cantidad efectiva de éter 4-ter-butilfenetilquinazolin-4-ílico o 4-cloro-5-etil-2-metil-N-[(4-ter-butilfenil)metil]pirazol-3-carbo xamida o 5-cloro-N-[2-[4-(2-etoxietil)-2,3-dimetilfenoxi]etil]-6-e til-4-pirimidinamina o 4-cloro-3-etil-1-metil-N-[4-(p-toliloxi) bencil]pirazol-5-carboxamida.
