Abstract: A flexible chest drainage bag or the like has an inlet with a flutter valve, and a venting outlet formed by a rigid or semi-rigid tube. The tube projects downwardly into the bag alongside the flutter valve to its lower end so as to resist folding of the bag in the region of the valve. The tube has an open lower end and several apertures along its opposite sides between the walls of the bag, so that the apertures are not obstructed by the material of the bag. One aperture is located close to the top of the bag to allow fluid to be drained from the bag when the bag is inverted. The upper end of the tube is external of the bag and is provided with a plastic cage to prevent occlusion of the tube.