back in 2013 i used hartz on my dog she was a mixed chihuahua and corgie well she started having seizures and we rushed her to the hospital and on the way she stopped breathing i had to give her mouth to snout to bring her back then she was throwing up yellow foamy stuff. The doc said it was from the parithamin (not spelled right) but that he had seen many dogs die from it. The company sent me a refund and that was all. Sadie had seizures for years where we had to cram pills in her mouth. So very sad.