An ostomy appliance comprising a base plate, said base plate having a first hole for receiving a stoma, ureter, or catheter and an adhesive wafer having a first surface to be attached to the wearer's abdomen back, or chest; a receiving member or bag releasably attached to the base plate, said bag having a second hole for receiving wastes exiting the stoma, ureter or catheter; and a disposable inner bag liner forming a second bag inside the receiving member and being releasably attachable to the base plate in a first coupling area by first coupling means, said disposable inner bag liner having a third hole for receiving wastes exiting the stoma, ureter or catheter and the receiving wastes exiting the stoma, ureter or catheter and the receiving member being releasably attachable to the base plate by second coupling means wherein the first coupling means is in the form of an adhesive flange projecting from the rim of the third hole and having a surface for releasable sealing against a second surface of the base plate facing away from the user provides an ostomy appliance combining the advantages of using a separate, flushable inner bags with an easy, safe, hygienic and discreet management of the collected waste with maximum safety against soiling parts of the appliance not to be substituted when substituting the inner bag, which inner bag may be used directly together with existing ostomy devices.