Up until recently, the only option for fleas has been topical, but now you can look at something much more dog-friendly; NexGard Chewables.
dog fleas control
Ask your Vet for Nexgard! Each chewable cost about $20. and one chewable is good for a month. One chewable should get rid of the fleas unless they are in the carpet and the dog’s living area. The Vet probably will want you to get more than one month supply.