A topical insecticide preparation is provided which can be safe to use and avoids many common deleterious side effects of conventional topical insecticides. The topical insecticide contains a combination of a first pyrethroid insecticide effective for killing fleas, a second pyrethroid insecticide effective for killing ticks, and an insect growth regulator (IGR). The topical insecticide preparation can be packaged together or packaged so that the first and second pyrethroid insecticides are stored separately prior to administration of the insecticide preparation to the animal. The combination of the first and second pyrethroid insecticides with an insect growth regulator results in an insecticide preparation formulated to have enhanced insecticidal activity against fleas and ticks compared to the effectiveness of the first and second insecticides used alone. Further, the combination of the first and second pyrethroid insecticides with an insect growth regulator produces an insecticide preparation having enhanced insecticidal activity against fleas and ticks while advantageously minimizing the total amount of insecticide needed for its effectiveness.