If your dog's anal glands are extruded black, it may be because the anal glands have not been squeezed for too long or the anal glands are inflamed. It is best to go to the hospital for examination to prevent the symptoms from becoming more serious. Dogs need to squeeze their anal glands regularly. If they are not squeezed for a long time, it will cause inflammation of the anal glands and blockage of the anus. In serious cases, it will affect defecation, and the dog's body odor will be relatively strong. It is best to squeeze it once a month or so.