Have you given him more attractive alternatives? Someone else may know if he's at the stage where he's teething, eleven months seems a little old to me. I know people who gave their teething pups washcloths (or dishtowels) soaked in chicken broth, twisted then frozen - it's yummier than furniture, and the cold soothes their gums. Of course, that was confined to the kitchen linoleum floor! Does he just chew when left alone, or at specific times?