I have a 6 month old American Bulldog and we have been trying to pay off his hospital bills from the time he chewed a toy and had it stuck in his belly so i bought Hartz becuase it was cheaper. The next day he broke out in a full body rash and everytime you would pet him he would shy away from you becuase it hurt. I had to take him to the vet to get antibiotics and the Vet told me all about Hartz!! It is very dangerous please do not use this! My mom also used it on her dog and the same thing happened. it is killing some animals. stick with the exspensive stuff!!!