We have a dog and 3 indoor cats. The dog only goes outside to use the bathroom, but invariably picks up fleas which come inside and affect the cats too. Last year, the fleas were so bad that the dog bit herself raw around the base of her tail. The vet said that she was allergic to fleas and recommended Comfortis at that time, but I thought it was too expensive, so I continued using a topical ointment on all 4 pets. We used Advantage Plus until it no longer seemed effective, then switched to Frontline. This summer has been hotter and more humid than normal, and the fleas have been really bothersome. After applying Frontline twice in 2 weeks and getting no results, I broke down and started pricing Comfortis. I started at Amazon and found the cheapest price through VetDepot. They contacted my vet, who called me. She asked me how much VetDepot was charging, and when I told her $70.99, she said,"Wow, that's a lot less than we charge." It took about a week to get the product, but when it arrived, we asked the dog if she wanted a treat. My daughter tossed it on the floor, and the dog ate it right up. Within 30 minutes, there was no more scratching. I'm thrilled with this product. When is it going to be available in a formula for cats?