Besides toxicity profiling we also try to understand how substances induce their toxicity in organisms. Therefore, we study the uptake and metabolism of compounds and identify were compounds interact within a cell or organism. With state of the art OMICS techniques (e.g. transcriptomics, metabolomics, proteomics, lipidomics) we investigate the mechanism of toxicity the so called toxic mechanism of action (tMoA) of compounds and groups of compounds. To identify the tMoA we apply in vivo models like zebrafish embryos and a variety of cell based in vitro assays. The tMoA can be used to improve risk assessment by helping to develop adverse outcome pathways (AOPs). Furthermore, the tMoA can be used to identify mechanistic links between compound exposure and disease development. By understanding the tMoA of compounds novel biomarkers and bioassays can be established which can be easily applied in high throughput screens. Such screens can be used to either classify toxic compounds (toxicity profiling) or to determine potential novel disease treatments.