Described are medical products, systems, and methods for treating fistulae having a primary opening, such as in the alimentary canal. Certain methods of the invention include providing an implantable material including a compliant sheet from biocompatible material, and forcing this sheet form biocompatible material into the primary opening so as to deform the sheet form biocompatible material to conform to and block the primary opening. The biocompatible material preferably comprises a remodelable material, for example, a remodelable extracellular matrix material such as submucosa.
