Zoonotic infections with Campylobacteraceae, the most common bacterial diarrhoeal pathogens, represent a serious problem in human medicine. C. jejuni as prototype but also others such as C. coli and C. concisus belong to these clinically relevant bacteria, with repeatedly occurring outbreaks and cases of fatal septicaemia. For this purpose, we want to extend our basic knowledge of the pathogenesis of Campylobacter associated gastrointestinal diseases. We will investigate the underlying mechanisms that contribute to the development of diarrhoea and inflammation. For this purpose, molecular and electrophysiological studies will be performed on human epithelial cell lines (HT-29/B6), epithelial cell-immune cell-cocultures, mouse infection models, and human intestinal biopsies. Preventive therapies will be studied using these experimental systems which includes vitamins (vitamin D), trace elements (zinc), dietary components (short-chain fatty acids), plant components (quercetin), whey components (lactoferrin), and traditional drugs (berberine), all of which have been identified to stabilise epithelial barrier function. The main focus is on multimodal protective strategies against C. jejuni in humans and farm animals on the basis of molecular barrier research.