Francisco Guarner is Consultant of Gastroenterology at University Hospital Vall d’Hebron, Barcelona, Spain. Member of the ‘Guidelines & Publications Committee’ of the World Gastroenterology Organization (WGO). Chair of the Steering Committee of the International Human Microbiome Consortium. Member of the Scientific Committee of Gut Microbiota for Health Section of the European Society of Neurogastroenterology & Motility. Member of the Board of the Spanish Society for Microbiota, Probiotics and Prebiotics.