As a retired groomer and having bathed over thousands of dogs first make sure he doesn't have a skin problem which can make them smell and follow your vets recommendation as to what medicated shampoo he needs to treat the problem.I have 2 large Rottweilers and they have a standing appointment for a good bath once every month by me.Make sure you use a DOG shampoo because their PH is not like humans and baby shampoo is actually not gentle for dogs.....My dogs are house dogs and they need to be clean and smelling good.....Hope I helped....