So i have two dogs, one of them is a super fat and fluffy chihuahua-thing. She's had fleas for a long time now, and we gave her some of that back medicine for it a few weeks ago, but the fleas are only getting worse! Her stomach and inner thighs are red and bare because she's been scratching them so much. The fleas are starting to infest my other dog and one of my cats too, I don't know what to do! Does anyone know a good flea medicine or shampoo that can easily and quickly get rid of fleas? Do dog flea medicines work on cats too???