There is provided in accordance with an embodiment of the disclosure a spray-on composition for the treatment and prevention of insect or arachnid infestation on a mammal comprising between 0.1% and 1.0% by weight dinotefuran. There is also provided in accordance with an embodiment of the disclosure a method for treatment of an animal at risk of insect or arachnid infestation comprising topically administering to the coat of the animal a composition comprising between 1 and 50 mg dinotefuran per kilogram of animal weight. Optionally, topically administering includes spraying on a majority of the area of the coat of the animal.
