We were pleased to order the Seresto Flea and Tick Collar for our cat. However, within 36 hours of placing the collar on the cat, he reacted with loss of hair and an apparent chemical burn on his neck and was becoming lethargic. When we described the problem to PetCareRX, the rep said "we don't have responsibility for reactions to our products." Apparently, there is no problem selling their products, but don't expect them to stand behind their products. I will never buy anything from them again. They lost not only a lifetime customer for a relatively small purchase cost, but also we are alerting our clientele not to buy anything from PetCareRX.