Dr. Castillo obtained his medical degree at the University of California, San Diego. He completed training in pediatric gastroenterology and liver disease at UCSF and remained on faculty there. He moved to Stanford in 1985 as co-director of the Division of Pediatric Gastroenterology, Nutrition and Hepatlogy. He became an active member of the Pediatric Liver Transplant Service in 1995 when Dr. Kenneth Cox and Dr. Bill Berquist came to Lucile Packard Children's Hospital. He was recently appointed Director of the Pediatric Small Bowel Transplant Program which compliments his long standing clinical and research interest in intestinal growth and absorption and function.