I am posting this only to warn others. I tried the hartz first defense product three weeks ago On my 8 year old boxer-hound mix. A couple days later he was vomiting every morning for a week or so. I saw him taking too long and noticed. Yesterday he developed facial paralysis and loss of balance. He actually fell down while trying to catch a ball and stumbles after shaking his head. I rushed him to emergency vet and she started him on an antibiotic and going to have more tests ran this week. He was healthy, perky, and full of life a month ago and now they said the paralysis might be permanet and he’s very lethargic. Take this product off the shelf!