I put a Hartz flea/tick collar on Ramona this spring. She had a spot appear on her face that looked like she’d been in a fight. I just waited for it to heal up. Next thing I know she’s losing hair on the bottom side of her neck. Then the open, oozing sores and constant scratching. I got her an appointment when she stopped eating. Before I could get her to the vet she found a hiding place in the alfalfa bales in the barn. We moved the bales. Then she dug under the floor of the barn. I had to cancel the appointment because I couldn’t get to her. I was afraid I’d have to tear the floor out. Finally, my boy got her to come out and we closed her in my workshop and rescheduled an appointment. By now she was a mess and smelled of rotting flesh. Hair just fell off of her and her sores left wet spots everywhere in my shop. I thought she was dying. When we got her into the vet he asked about the collar. He told me that first of all those collars don’t work and secondly some animals have allergic reactions. I was immediately angry. You mean I did this to her? I bought a product to keep her healthy and darn-near killed her! He cut the collar off and gave me some anti-biotic cream. I applied it and within a day she was showing improvement. Now, a couple weeks later she’s finally starting to grow back some hair. She’s acting normal and playing again, eating fine and back to barking at coyotes. Praise God! Don’t use Hartz!