I've only used it for cats. It doesn't work for ticks. My dog got into a nest of ticks or something the other day so they recommended Frontline Plus. I got the FP for the cats too instead of the multi on the advice of the vet staff. She said that with as bad as the ticks are this year, it would be best to go for a few months using the FP for the tick protection and then go back to the multi for the worms and mites after the summer.