Growling is a form of aggression in dogs. Dogs that growl at people may have an underlying problem, such as a fear of strangers. Growling by itself is not dangerous, but if the underlying issue is not dealt with, growling could turn to something more serious, such as nipping, lungeing or even biting. To protect your dog and the people around your dog, start dealing with the problem immediately.
Take your dog to see the veterinarian to make sure a medical issue is not causing the growling. Dogs that are uncomfortable or in pain might take it out on people.
Ask your veterinarian to recommend an animal behaviourist to work with. Because growling at people can be serious and can lead to someone getting hurt, it is not a problem you should tackle alone. Get help from a professional.
Put a muzzle on your dog when it is around people while you are working on the growling problem. This protects the people and your dog.
Work closely with the animal behaviourist. A professional can help you identify the cause of your dog's aggressive behaviour toward people. Again, because of the potential danger, this is not a problem you should try to resolve on your own.
Reward your dog when it is around people and does not growl. Reward can be in the form of attention, affection or a treat. Positive reinforcement can go a long way when training your dog not to growl at people.
Never punish a dog for growling or any aggressive behaviour. This can heighten the aggression, turn it toward you or cause more fearful behaviours in your dog, and it will not do anything to fix the problem.