I bought this bitter Apple spray to deter my lab puppy from chewing on the furniture, walls and pretty much anythinf else he is not supposed to chew. I found it works pretty well but I did have to reapply quite often to keep him from chewing. I like that there really isn't much of a smell to it so I can spray it and not have a lingering smell. I have tried other sprays but the smell was so bad it kept me away more than my dog.
I have also used this to prevent chewing on one of my dogs during allergy season. It works really well as long as it is reapplied a couple times a day.