A few years back I used Hartz on my cat as he got outside and came back littered with fleas. 20 minutes after treatment he started having seizures, I immediately bathed him with Dawn dish soap and a vegetable sprayer. After about 10 minutes the seizures stopped, another 30 and he was his normal self again. A vet visit later confirmed what we had thought, that the Hartz was the culprit. He prescribed us a special flea shampoo that we used up until he got nabbed by coyotes 2 weeks ago. We recently got a dog now and after doing some research, saw that Hartz changed their formula. Knowing what I knew from the cat, I decided to give it a try and just monitor him very closly. My wife and I applied the treatment and all was going well until he went to sleep. He started twitching, breathing heavily, and would not open his eyes, as if the room was spinning. After trying to do everything I could to get him to respond, I bathed him with a removable shower head and loads of Dawn. Instantly his breathing calmed down and 20 minutes later, he’s his energetic self again. We’re going to the vet this week to get a shampoo just for him. If you do use any over the counter flea product, watch your pet closely, it’s not going to be too late if you catch a reaction within the first hour.