Described are medical graft products, systems, and methods for treating fistulae. Certain products of the invention are configured to have portions residing in and around a primary fistula opening, e.g., one occurring in a wall of the alimentary canal. One such product includes a biocompatible graft body which is configured to block at least the primary opening. The graft body includes a capping member, which is configured to contact portions of the alimentary canal wall adjacent to the primary opening, and an elongate plug member extending from the capping member, which is configured to extend into at least a portion of the fistula. In certain embodiments, a graft body component has the capacity to expand or otherwise change form to provide a suitable capping arrangement. Such a component can include a resilient wire frame, e.g., one that is self-expandable or one that requires at least some manipulation in order to expand.