A continent ostomy port device has a face plate defining an aperture alignable with the opening of a stoma in the user's body and a closure adjacent to the aperture is adapted to permit covering and uncovering of the aperture in the face plate. A catheter extends from one side of the face plate proximally, and one end of the catheter is disposed within the ostomy site when the port device is in use. The catheter has continuous exterior and interior side walls, the latter defining a major lumen and is sized and shaped for non-surgical insertion through a stoma to a sufficient distance that the presence of the catheter within the stoma provides a barrier which reduces the incidence of prolapse, without the use of extraneous, externally applied materials or additional surgery. A removable cartridge fits snugly and slideably within the major lumen of the catheter of the device so as to prevent inadvertent escape of body waste material from the stoma when the cartridge is in place, without use of an ostomy bag, and to clean the interior side wall of the catheter as the cartridge is pressed into the major lumen. An anti-reflux valve is activated to prevent escape of body waste and deactivated for passage of fluid. Retaining structure is connected to the catheter, and is non-surgically, snugly fittable into the stoma, to cause the port device to be self-retaining in a normal use position within a stoma, without surgery or fixation materials.