I used Hartz Ultraguard drops on my 4 month old kitten (drops recommend 12 weeks of age) and he instantly started showing signs that something was wrong. He was acting like he was in pain, shaking his head and running through the house. I went to the internet to find out why and found this site. I read all the stories about losing pets. I started sobbing and chased him down, finding him curled up in the hall. I could tell by how he looked, he was in pain. This stuff must have been burning him. I instantly washed him in Dawn until I couldn’t smell the poison anymore. I’ll keep an eye on him and if there’s any change from his normal behavior, I’ll post.