An adult individual typically harbours a few hundred grams of bacteria in their digestive tract. Recent findings have brought forward the fundamental role of this microbiota in determining drug efficacy, mode of action and side effects. Yet, such interactions at the microbiome level remain unknown for the vast majority of the drugs and for other xenobiotics that we are exposed to (e.g. food contaminants like pesticides). The overarching goal of Kiran’s research programme is to discover and model complex (xeno-) metabolic networks emerging in the gut microbiota and thereby gain mechanistic insights into microbiome-mediated toxicity. To this end, this interdisciplinary programme brings together computational (metabolic modelling, bioinformatics, chemo-informatics and machine learning) and experimental (in vitro microbiomics, metabolomics and chemical genomics) approaches.