I’m disappointed with PetFriendly. I used this monthly on my cat and followed instructions to a T, yet my cat got fleas which resulted in worms. I had to take my cat multiple times to the vet to be prescribed deworming medicine as well as a medication to kill the fleas on her and resumed using the PetFriendly on a monthly schedule as usual. Yet the fleas always came back. I contacted PetFriendly multiple times to be told “you must have an infestation.” I don’t. Other cats in my apartment did not have fleas or worms and were on prescribed medication from veterinarians. I’m thoroughly disappointed in PetFriendly’s lack of care & action after contacting them multiple times about my concerns. I would recommend just going to the vet and getting the medicine from there. Otherwise you may have problems like this.