In my opinion, the PetSafe No Bark Collar will not harm your dog. The PetSafe Bark-control collar delivers a harmless static shock to the dog whenever it barks. It is designed to train a dog, not punish it. Therefore, the shocks are not strong enough to cause harm. According to a university study of the PetSafe No-Bark Collar, involving adult shelter dogs, there were no no long-term adverse effects, and and all of the dogs reduced their barking by the second day. PetSafe also offers an alternative collar, that uses a harmless spray instead of a static shock as a bark deterrent.