Does pine tar work on dogs too?

Pine tar soap definitely does not help kill or prevent fleas attacking your dog. The best flea treatments/preventions are monthly 'spot on' treatments such as Frontline, Advantage and Revolution which you can get from your pet shop or vet. Dogs have a different acidity to their skin than we do, so human soaps and shampoos can disrupt the natural state of their skin leading to dryness and itchiness. Specialised dog shampoo should always be used - never use human brands.