In a 55-year-old woman, a 1 x 5 cm fistula developed in the ileoanal anastomosis after restorative proctocolectomy with J-pouch ileoanal reservoir and temporary ileostomy for intractable ulcerative colitis. The fistula extended between the pouch and the sacral bone. Lasting closure was achieved by intrafistular placement of a collagen sponge containing gentamicin and soaked in metronidazole solution and pouch drainage through a transanal Foley catheter.