The invention relates to a device for the sealing closure and/or for the space-filling tamponade of hollow organs or other cavities in the human body, comprising a 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 sealed or to be applied with a tamponade. The device comprises an isobarically acting controller (3) for the filling pressure within the interior of the balloon, said controller comprising a volume reservoir (3) arranged extracorporeally outside of the body and a feed line (6) for communicatively connecting the extracorporeal volume reservoir of the controller to the interior of the balloon. The connectable feed line between the balloon and the controller has a flow-directing non-return valve (26) which prevents a return flow from the balloon to the volume reservoir of the controller while a non-flow-directing throttle element (27) is also provided which allows a slow volume equalization between the balloon and the volume reservoir.
