I recently tried Hartz Ultra Guard Plus topical flea and tick prevention for cats and kittens 12 weeks and older (for 5 pounds and over). I had spotted a few fleas on 2 of my 3 cats, so I thought one dose each might get rid of them before they became a bigger problem. I applied it first to my long haired cat (she is the bigger of the 2), and she was ok. So, I then put it on the other cat. Almost immediately after the application, he started racing around the house! He was all puffed up, panting then hissing, screaming out like he was in pain, and just completely freaking out! He could have passed for demon possessed the way he was acting. I immediately tried to call the 800 number on the box and got a voice recording directing me to an 888 number. No luck reaching anyone. It was after 6, so no vets offices were open and the emergency hospital is an hour away. I wasn’t sure if it was burning his skin or if he’d somehow licked it. I raced him to the bathtub and scrubbed the solution off of him. Luckily, shortly after the bath, he returned to normal. It’s been 11 days since the applications. He is fine now as far as I can tell, but the first cat with the long hair has been losing her hair in clumps where the Hartz was applied. After reading other people’s testimonies, I consider myself lucky that mine are still alive and healthy! I wish I would have found this site before I tried the flea solution!! I knew Hartz products have been on store shelves for decades, so I figured they must be effective and safe. I am going to tell everyone I know about how unsafe and dangerous their products are. They shouldn’t be allowed to be sold at all.