To characterize modes of action of substances as well as their cytotoxic effects Bionas GmbH has developed a new screening system to allow the continuous recording of how an active substance can act (Bionas^® 2500 analyzing system). In the pharmaceutical and chemical industry as well as in environmental science it is important to acquire as much information as possible about the metabolic effects of an active substance or there cytotoxicity. With the Bionas^® 2500 analyzing system metabolically relevant data including oxygen consumption, acidification rate and the adhesion (cell impedance) of cells can be measured in parallel, on-line and label-free. Using e.g. ion-sensitive field effect-transistors (ISFET) and electrode structures it is possible to observe metabolic parameters non-invasively and continuously over longer periods of time. The system has already been established for several cell models, cell lines as well as primary cells. The strength of our system can be found in the continuous data collection during the whole application period. Dynamic, reversible and / or regenerative processes can be observed in one and the same culture. Adaptation effects through repeated addition of compounds can also be observed. A long application period (hours to days) allows more realistic compound concentrations as it is possible in short-term experiments. This advantages result in a higher information content compared to end-point-methods. It also offers the advantage that regenerative effects can be observed during the same test run.