The Fourth Gut Microbiota For Health Summit aims at translating the most recent advances for the medical community. The American Gastroenterological Association (AGA), the European Society for Neurogastroenterology & Motility (ESNM), the European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN), the European Crohn’s and Colitis Organisation (ECCO), and the European Association for the Study of the Liver (EASL) nominated a joint scientific committee to organize a robust program for the Summit. This international event will take place in Barcelona (Spain), on March 14 and 15, 2015.