A discharger for a flowable medium, having a pumping device with a pumping chamber which is closed off on one side by a longitudinally movable piston, is provided.The pumping chamber on the piston side is hermetically sealed against an environmental atmosphere outside the discharger by a gas-impermeable and at least partially flexible diaphragm, and the diaphragm, in its marginal region, is fixedly connected to a housing of the discharger.The discharger is used for high sealing requirements against the ingress of impurities.