Isolators to produce or examine highly toxic substances. Highly toxic substances are produced and examined in the cytostatic isolator. Cytostatic drugs are used to treat cancer. This is a cytotoxic; therefore no substances must be emitted outside. To ensure this the isolator is operated with vacuum and operator environment and product protection must prevail. The cytostatic isolators consist of a lock for material entry which can be decontaminated using H2O2, a working chamber and a lock chamber for material exit incl. a material lock (optional liner system). The clean room class A according to GMP is attained within the working chamber. The whole system can be sterilized with hydrogen peroxide before starting work or in regular intervals.