We aim to understand how substances give rise to toxicity in organisms. For this, we study the uptake and metabolism of compounds, identify where compounds interact within a cell or organism and what the potential toxic effect can be. We investigate the mechanism of toxicity or toxic mechanism of action (tMoA) of compounds and groups of compounds, for example using state-of-the-art OMICS techniques (e.g. transcriptomics, metabolomics, proteomics, lipidomics). To identify the tMoA we apply in vivo models like the zebrafish embryo model and a variety of cell-based in vitro assays. The tMoA can be used to improve risk assessment and support the development of adverse outcome pathways (AOPs). Furthermore, the tMoA can be used to identify mechanistic links between exposure to a compound or a chemical mixture and disease development. By understanding the tMoA of compounds, novel biomarkers and bioassays can be established that can be applied in high throughput screening or mechanistic toxicity studies. Such screens can be used to either classify toxic compounds (toxicity profiling) or to determine potential novel disease treatments.