I wish I would of seen this website before I gave Hartz flea control to my dog. He was a 6 year old Saint Bernard. I could not figure out what was wrong with him. He would not eat or drink. We visited the vet several times and had blood work done. Finially the bloodwork showed a high toxicity level. I was racking my brain trying to figure out what was poisioning my Dog. Finially I told my vet that I used Hartz drops on him and he said that the medicine poisioned him. He said he has seen it on several dogs and cats. I had to put him to sleep because his kidneys shut down and he was having seizures. I could not stand to see him suffer. Two days before Christmas is not a good time for a death especially when I have 2 children that have lost there buddy. It was a sad time for all of us. Never again will I use anything without contacting our vet.