A system has an ostomy bag and a waste collecting bag. A discharge passage of the ostomy bag can extend into a receiving passage of the collecting bag to receive waste and flushing liquid from the ostomy bag. Slide fasteners connect the passages during the discharging operation. Nubs on the discharge passage engage registration openings in the receiving passage to register the slide fasteners with each other and facilitate their engagement. A vent opening with further slide fastener can be opened to vent gas or to admit flushing liquid into the ostomy bag. A slide fastener extending across the receiving passage of the collecting bag is sealed after the ostomy bag has been clamped and prior to disengaging ostomy bag from the collection bag for sanitary disposal. A hygienic cap is placed over the opening of the ostomy bag to contain any residue contaminants.
