Dr. Ooi Choon Jin specializes in gastroenterology, hepatology, and nutrition, with a strong clinical focus on conditions like ulcerative colitis, Crohn’s disease, and Helicobacter pylori-related disorders. He routinely performs advanced procedures such as gastroscopy, colonoscopy, balloon-assisted enteroscopy, and capsule endoscopy. He served as President of the Gastroenterological Society of Singapore from 2006 to 2008 and later chaired the Chapter of Gastroenterologists at the Academy of Medicine, Singapore from 2011 to 2013. As Secretary General of the Asian-Pacific Association of Gastroenterology, he continues to play a key role in advancing the field regionally.