Do not use this product! I applied two tubes to my cat, obiously once a month like the instructions say to do. The first application went fine. The next month i applied the 2nd dose and within 24 hours my cat was deathly ill. She was extremely lethargic and would not eat or go to the bathroom for a day in a half. She also could not stand on her hind leg. The next day i took her to the vet only to discover that the vet and vet techs ALL said DO NOT USE this on any type of animal and how surprised they were that the FDA is still allowing this product to be sold. My cat who is 15 got a steroid shot and some fluids and seems to be doing a little better. I am keeping a close eye on her and can only hope for the best. The vet did tell me that she has severe nerve damage which can be associated with Hartz Medication. Please people do thorough research before giving your animal’s any type of medicine.