The inside of the dog's ears is dirty and there is brown stuff, which is usually caused by ear mites. It is also accompanied by a sour smell. The dog also often scratches its ears, shakes its head, shakes its head, etc. You need to help the dog in time. Get treatment or the ear mites will get worse. To treat dog ear mites, you can use pet ear cleaning solution and clean it 1 to 2 times a week. At the same time, you should also help the dog with external deworming. If you persist for a period of time, it will get better.