What is the best shampoo for fleas on dogs?

There are many, many brands out there. If your dog has a real problem with fleas, it may be he is getting them from your yard. When treating your pet for fleas, if you expect to keep him from getting them again any time soon, you must treat your house and yard (where he plays and goes potty). Treating the bedding is a must as well. If your dog travels in your car, guess what, this area should be treated as well. If your dog bites at himself trying to scratch a flea, he may ingest it. This can cause tape worms to grow in your dogs stomach. These are the little white "rice like" wiggly things in your dogs fresh feces. So I would suggest you apply a monthly flea preventive such as Frontline or Advantage so your dog has a better chance of not getting any kind of internal parasite. I also suggest your contact your vet.