Dr. Guillermo Álvarez Calatayud is a specialist in Pediatrics who is particularly interested in the area of Gastroenterology in children and adolescents. He is a physician who has over two decades of experience in the sector, mainly as an Attending Physician at Gregorio Marañón University Hospital and as Area Specialist Physician at HM La Esperanza Hosptial.

He has combined clinical activity with teaching as a professor of Pediatrics for several university programs. In addition, he has chaired the Spanish Society of Microbiota, Probiotics and Prebiotics and has been the secretary of the Iberoamerican Society of Microbiota, Probiotics and Prebiotics. He has always defended the use of these drugs in pediatric patients based on expert knowledge in the area.

• Specialist in Pediatrics at HM La Esperanza Hospital
• Attending Pediatrician in the Pediatric Gastroenterology Department at Gregorio Marañón University Hospital
• Full Professor of Pediatrics at the European University of Madrid
• Doctor of Medicine, Complutense University of Madrid
• Master's Degree in Pediatric Gastroenterology, Complutense University of Madrid
• President of the Spanish Society of Probiotics and Prebiotics (SEPyP)