So my one year old cat recently got tape worms. I went to the vet and got her some topical medicine for it, which worked, but I also wanted to get her a flea collar to help keep the fleas away. This was merely because it was an infected flea that caused her to have tape worms to begin with. I’ve heard the worst reviews about hartz and I knew it was bad, but I was in such a hurry when grabbing a flea collar from walmart that I didn’t even notice the brand. When I got home, I put the collar on her, but then read that I should wait at least 30 days if I had already applied any other medicine to her, which I had already put the topical worm medicine on her that same day, and then I realized the product brand, so I immediately took the collar off of her.. About 30 minutes to an hour later, I started feeling HORRIBLE.. Before I knew it, just from the little contact I had with the collar, even after I washed my hands, I ended up throwing up black liquid, had black diarrhea, and all of a sudden I had the worse UTI known to woman, my stomach was in so much pain and the only place I felt comfortable was sitting on the toilet. I feel much better today, only I still have diarrhea, which consists of nothing but blood. I know it wasn’t anything other than the flea collar that caused this to happen to me because I had just got done running my normal 6 miles, I was perfectly fine before. I’m just so glad that I took that collar off my cat when I did, because if Hartz causes such a horrible reaction in humans, imagine how it must effect our pets! I’m absolutely outraged. I just hope I don’t turn up dead in the next few days.. This product can go to hell.