I think they can work for some dogs and I think they are more humane than the shock collars. Although some dogs may not be phased by it. We had a dog at the shelter we used a cintronella collar on to get him to calm down with barking. It did not phase him when it sprayed him. Some dogs are just going to bark and nothing will phase them. I am glad the spray bottle is working with him, better than paying $70 for a cintronella collar that may not work.