Treated the cat and dogs with flea treatment this morning, havn't seen any fleas but the dog was having the odd scratch and they were due another treatment. Treated them with advantage (first time I had used it on my younger dog but have used it on the other dog and the cat many times ), since treating the dog he has been scratching twice as much. Does this mean he does have fleas and they are going crazy? Or does it mean he has had a reaction to the treatment? It's hard to see fleas on him as he is black, my other dog is white and I havn't seen any on her, it's usually the cat that picks them up but havn't really seen any on him either.