Treatment and prevention of infestations in dogs by ticks (Ixodes ricinus, Dermacentor reticulatus, Rhipicephalus sanguineus, Ixodes scapularis, Dermacentor variabilis, Haemaphysalis elliptica, Haemaphysalis longicornis, Amblyomma americanum and Amblyomma maculatum) and fleas (Ctenocephalides felis and Ctenocephalides canis). Treatment of infestations by chewing lice (Trichodectes canis). Prevention of environmental flea contamination by inhibiting the development of all flea immature stages. The product can be used as part of a treatment strategy for the control of flea-allergy dermatitis. Elimination of fleas and ticks within 24 hours. One treatment prevents further infestations for five weeks by ticks and for up to five weeks by fleas. The treatment indirectly reduces the risk of transmission of tick-borne diseases (canine babesiosis, monocytic ehrlichiosis, granulocytic anaplasmosis and borreliosis) from infected ticks for four weeks.