Xiaopeng Bai
Assistant Professor, Medicine

Dr. Xiaopeng Bai is a clinician-scientist and gastroenterologist specializing in the pathophysiology of functional gastrointestinal disorders. His research bridges basic science and clinical practice, focusing on how the intestinal microbiota, immune system, and stress pathways interact to regulate gut motility, epithelial integrity, and neuroimmune function.
After earning his MD and PhD at Kyushu University in Japan, Dr. Bai trained extensively in gastroenterology, smooth muscle physiology, and endoscopic techniques. His early research in Japan contributed to the understanding of esophageal motility, lower esophageal sphincter tone regulation, and the role of ion channels and prostaglandin signaling in gastrointestinal function. He later completed a postdoctoral fellowship at McMaster University, where he expanded his focus to microbiota-host interactions and the gut-brain axis. Dr. Bai’s body of work spans fundamental discoveries in neurogastroenterology and mucosal immunology, including the microbiota-dependent regulation of intestinal motility, the impact of chronic stress on epithelial regeneration, and immune-neural crosstalk in post-infectious gut dysfunction. His research integrates basic mechanisms with translational insights, using both human-derived samples and advanced preclinical models to advance diagnostics and therapeutic strategies for functional GI disorders.
His lab uses gnotobiotic and humanized mouse models, multi-omics profiling, and confocal imaging to study interstitial cells of Cajal, glial cells, and muscularis macrophages. Dr. Bai’s long-term vision is to develop microbiota-based diagnostics and personalized therapeutic strategies for irritable bowel syndrome, chronic constipation, and gut dysfunction following Clostridioides difficile infection.
He is also actively involved in advanced endoscopic techniques at McMaster University Medical Centre and supervises translational and clinical gastroenterology trainees.