I put a collar own my 1 year old dog, rather than drops about 3 weeks ago. Suddenly, I noticed everything he used to love to eat, he completely quit eating. Not anything, not dog food, no “people food”, he loves all kinds of fresh fruit, veggies, meats and he would not eat a bite. I got a new puppy a week ago, & they both got ill within a few hours yesterday afternoon. The puppy did not have a collar on but had been playing with my old fur-kid “peanut” & got some of the “stuff” on the collar in his mouth. Within 20 minutes the puppy was throwing up and had diarrhea so badly, and she had been perfectly fine 30 minutes before this. I took the collar off of Peanut last night, and this morning he ate just like he was starving!!! He began eating everything that he usually enjoys. I am so mad at this company Hartz AND YSELF for NOT checking things like this out before using a product. I usually do and for some reason did not do my research this time. I WOULD NEVER USE ANY of Hartz products again, and after seeing HOW MANY CONSUMER REPORTS are up that people had their pets even die, I am relieved that I feel mine will be okay. I am glad that I did decide to remove that horrible collar and will let my Vet take care of flea’s etc now even if it costs more, it’s worth it!!!