Dogs always seem very harmless and playful. You don't think anything wrong of a dog licking you but what you didn't know is that you can get diseases that can be deadly.  Sometimes you may not notice that your dog is eating something that you wouldn't particularly want near your face. When your dog licks you, the amount of bacteria that is carried in the saliva is harmful. Bacteria isn't always carried in a dogs saliva. Dogs spend half their life with their noses in nasty corners or hovering over dog poop so their muzzles are full of bacteria, viruses and germs of all sorts. Ringworm is also one infection that can easily be carried by dogs. You always need to be careful with your dog and try to keep them clean.