My Shadow seems to have bounced back well. He and his dad were running all over our house this morning. I called Hartz when I got to work, and the lady told me that the shaking was normal and that the product wasn’t harmful. She said that it gave him a tickling sensation. I was so furious. Since I didn’t take him to the vet, I can’t get a statement saying that their product is what casued it all. I will be filing complaints to everyone I know to though.