Chief of Pediatric Gastroenterology/Pediatric GI Fellowship Director Dr. Thomas Wallach is a physician scientist and pediatric gastroenterologist currently taking new patients. Video introduction and informational videos are available here. Training: Dr. Wallach attended Pomona College, and completed his medical education at the Medical College of Wisconsin. He then completed a pediatric residency at Columbia University right here in New York, followed by an extended research fellowship in Pediatric Gastroenterology at the University of California, San Francisco, where he engaged in research focused on the regulation of the intestinal epithelial barrier, as well as advanced training in pain medicine. Expertise: Dr. Wallach is an expert on diseases of the intestinal epithelial barrier, with a specific focus on diseases of gut-brain interaction like irritable bowel syndrome, or other non-inflammatory causes of abdominal pain. Having trained at UCSF, a preeminent research site in inflammatory bowel disease and liver transplant center, he also has notable expertise in IBD, celiac disease, and liver diseases.