The König group applies Systems Medicine and Systems Biology to study drug metabolism and liver function. We use computational modeling, data science, bioinformatics analysis and machine learning on biological, medical and clinical data. Main research topics are (i) predictive modeling of biomedical systems with special focus on the liver; (ii) development of digital twins using physiologically based pharmacokinetic (PBPK) models, (iii) reproducible and open research, and (iv) FAIR data and workflows. Key projects are the personalized evaluation of liver function tests, multi-scale modeling of the liver, and development of databases and workflows to support reproducible, open and FAIR research. Within our research we generate predictive digital twins of the individual human physiology. Such models can provide important insights in inter-individual differences and personal treatments, e.g., individual dosing of medication or effect of lifestyle factors on drug metabolism.