I recently bought a Hartz flea collar for my cat and while wearing the collar she seemed very restless and agitated. We attributed her odd behavior to her age (she’s 15 years old). After about a week of wearing the collar, we took it off in order to give her a bath. Upon removing the collar we were surprised to find the fur beneath is was gone and the skin was red, bloody, and irritated. After researching Hartz, I found that chemical burns from their flea collars are not uncommon. I’m glad we noticed before the burns got any worse! I will NOT be buying Hartz products again and I will ensure others know the dangers of their flea products.