The invention is directed to a device for the sealing occlusion and/or for the space-filling tamponade of hollow organs or other cavities in the human body, comprising a preferably fully and residually formed balloon (2) which applies a sealing pressure that is as constant as possible to the wall of the organ to be occluded or tamponaded. The device comprises an isobarically acting regulator (3) for the filling pressure within the interior of the balloon, the regulator having a volume reservoir (3) situated extracorporeally outside of the body, and a feed line (6) for communicatively connecting the extracorporeal volume reservoir of the regulator to the interior of the balloon. The connecting feed line between the balloon and the regulator has a flow-directing one-way valve (26) that prevents backflow from the balloon to the volume reservoir of the regulator, while a nonflow-directing throttle element (27) is provided which allows a slow volume compensation between the balloon and the volume reservoir.