Abstract: The invention provides an ostomy bag assembly comprising outer (2) and inner (4) bags secured to one side of an adhesive flange (6); the adhesive flange (6) having means defining an orifice to enable bodily waste from a stomal opening to be received by the inner bag; wherein the adhesive flange is of laminar construction and comprises, in sequence, from a body-contacting surface outwards: (a) a bioadhesive layer (10) for securing the flange to a body surface of a patient about the stomal opening; (b) a first polymeric support layer (8) attached to the bioadhesive layer (a); (c) a heat sealable layer (16) having a heat sealable adhesive surface which releasably bonds the heat sealable layer to the first polymeric support surface; (d) a second polymeric support layer (14) bonded to the heat sealable layer; (e) a weldable polymeric layer (18) to which the inner and outer bags are attached, the weldable polymeric layer being bonded to the second polymeric support layer; the adhesive flange having an annular cha