Abstract: An arrangement for the sterile/aseptic production and/or filling of pharmaceutical products contains a housing which, with the exception of an inlet and an outlet with a clearly defined cross-section, is closed in an airtight manner. Through the air inlet air is forced via a filter into the interior of the housing. The air passes out of the housing through the air outlet or channels. The size of the cross-section of the air outlet and the performance of the ventilating device are matched in such a way that within the interior of the housing there is a laminar unidirectional or combined airflow and a constant overpressure with respect to the pressure outside the housing. This overpressure is kept at a constant value by a regulating device. With respect to the cleanness and the protection of the product obtained, the arrangement is comparable with an isolator, but can be manufactured, installed, validated and operated much less expensively.