I put Hartz Ultraguard flea & tick drops on my large Aussie with no reaction, but my small Aussie was poisoned by just playing with him. At first he was wired and seeing moving things that weren’t there. As he progressed he lost all balance and depth perception.
We rushed him to the vet hospital, he was in ICU for 2 days. We didn’t think he was going to make it. He tremored and shuttered for a week. I called Hartz and they told me that they had never heard of anything like this before. What a crock. I had them transfer me to there medical emergency vet and I got the same from her. Luckily we had taken him to a great vet hospital and they knew how to handle poisoned dogs. I was amazed that Hartz would lie to me and even more amazed when I found this website. Hartz should be ashamed of themselves for selling these products that hurt so many animals.