It depends on your dog. One of my dogs loves to bark. He will ignore everything else around him when he barks. Saying "No!" to him wouldn't have any affect on him at all so I squirt him with water instead. I also say "Good quiet!" when he stops. It seems to be working because I want him to be able to bark now and then but when I say "quiet!" he'll stop (only when he's inside..when he's outside, it's a different story ).