I have two dogs (one inside, one outside) and four cats ranging in age from 1 year to 5 years. This year has been the first that we have had a serious flea problem. Not having a lot of money to infest, we naturally try the products that are readily available and not too expensive. So we thought we’d try Hartz products. The flea sprays made my cats droll and half sick and didn’t seem to affect the fleas at all. The powder was also a complete waste of time. At least it didn’t make them sick. The flea collars were horrible. After wearing them for about three days, I saw that all of their necks were extremely sore and raw. I honestly didn’t know if was from them scratching at the collars (none of my cats wear any kind of a collar) or if it was from the flea collar itself. After viewing the picture on your web site of that poor cats neck, I am now convinced that it was the collar after all. Luckily, I took their collars off, and they all healed up. How can Hartz be allowed to sell thing like that the can be so harmful to cats? I am going to contact Hartz to let them know that their products are junk. I am glad that you have this site. You have opened my eyes to something that I suspected all along. That Hartz products are no good. Thank you for caring!