Prof. Messmann is director of the III. Medical clinic of the University Hospital Augsburg and since 2021 professor for internal medicine with a focus on gastroenterology. 2008 Chairman of the Endoscopy Section of the DGVS, 2010 Congress President of the DGIIN, 2012 President of the DGEBV, 2014 President of the Society for Gastroenterology in Bavaria, 2015 to 2016 President of the German Society for Colon Proctology, Member of the Board of the European Society for Endoscopy (ESGE) as well as a member of the Advisory Board of the DGVS and Deputy Secretary of the Endoscopy Section of the DGVS. Editor of numerous original works with a focus on diagnostic and interventional endoscopy as well as intensive care medicine and gastrointestinal oncology. Editor of numerous books (internal intensive care medicine, teaching atlas of colonoscopy, clinical gastroenterology, gastrointestinal oncology). Head of the Colon Cancer Center Klinikum Augsburg. President of the European Society for Gastrointestinal Endoscopy from 2021 to 2023.