A tamponade for nasal cavities or sinus cavities for tamponading a cavity of the nasal tract in the region of an ostium leading to the cavity with uniform force, comprising a thin-walled balloon which is made from a soft foil-like, only slightly expandable, smoothly folding polyurethane material, with a wall thickness in the range of 5 to 50 μm, which is already completely shaped with the required tamponade dimensions or greater at the time of production, and can therefore be expanded without application of filling pressure, and said balloon occupies the respective, generally irregular-shaped cavity and the ostium of same when in the filled condition, through the development of forces that are as uniform as possible on the structures exposed to the balloon in such a way that a distal segment of the balloon is located inside the cavity where a tamponade is to be applied, a proximal segment of the balloon is located upstream of the cavity and a transostial segment of the balloon extends through the ostium and connects the distal segment of the balloon to the proximal segment of the balloon, wherein the transostial segment of the balloon is tapered relative to the proximal and distal segments of the balloon in the deployed state of the balloon, and the nasal cavity or sinus cavity tamponade is anchored in the transition region and reliably secured in position.