Bests & Worsts Reviews from Amazon

I originally gave this product 5 stars because it seemed to be a miracle solution for my 11yr old male Maine Coon. He gets terrible fleas and even drops had stopped working. This got rid of his fleas, but something much worse eventually happened. We started noticing that he was drinking and eating constantly but wasn't getting fat, if anything he seemed skinnier. We took him to the vet for the senior lab panel that the vet had recommended at his yearly checkup earlier this year. First off, we were astonished that he had dropped from 9 to 6.6 lbs!!! We thought maybe it was diabetes, but that was ruled out, along with kidney failure, thyroid, and just about everything else. The vet was stumped. Meanwhile, our cat was getting sicker and sicker. He had not only diarrhea 7-8 times a day but brown water would leak out of him and we had to wash our sheets daily. He was lethargic, only wanted to lay huddled in one spot and when he did get up, his back legs often stumbled. We assumed that he was just dying of old age and we even suggested having him put down. He seemed so miserable. Then one night my husband said, "When did all this start exactly? Before or after he got that collar?" I slowly said, "A week after..." And it dawned on us. We never suspected the collar because the vet herself recommended it, had it on all her cats, and in all the tests and vet visits she never suggested it was the collar causing the symptoms. I Googled Seresto symptoms and there's not much feedback out there since it's new, but there is a lady in the UK whose cat had some similar symptoms to ours. I tore this expensive collar off without a second thought. I mean, we couldn't be sure that he wasn't just dying, but I figured if he was dying anyway, we didn't care about fleas. Well, it's a month since we removed the collar, and he has improved almost 100%. No more diarrhea, is back up to 8lbs, has his energy back (caught a bird this morning). It was definitely the collar causing the problems. He had no other treatments or changes. I'm not telling people not to use this product, as I understand it works wonderfully for most cats and very few cats will have reactions to it. But I want there to be a black box warning on the product that if you cat develops diarrhea after wearing this collar, to remove it and seek vet help immediately. I want people to be aware that the chemicals in this can make your cat very ill. Everyone I've told about this says, "Well, of course, flea collars are terrible." I tell them, oh no, but this one was new and different, and they just give me a pitying look, and I realize how stupid I was.