spent $36 for one month to protect my dog from fleas, ticks and heart worm. It is supposed to start working in a couple hours. 5 days later I look at this white dog and it looks like fish coming to the surface of a pond and going back under. My dog looks like she is sprinkled with pepper and all sizes so I know they have been there for days. I switched cause she started scratching while on Next guard. anyadontDont Dthing actually User's recommendation: Dont waste your money. Plus seeing a lot of health risk. Disappointed this was recommended by my vet!