Board-certified in both gastroenterology (1989) and internal medicine (1984), John J. Duque, MD has practiced in Chula Vista since earning his fellowship at Scripps Clinic following an MD from the University of California San Diego School of Medicine (1981) and an internal-medicine residency at UC Irvine. His diagnostic workload spans colonoscopy, upper GI endoscopy, and evaluation of inflammatory bowel disease and GERD — conditions where dietary management through practitioners such as Lani Rausa, RD - Dietitian Nutritionist becomes integral to long-term symptom control. Affiliated with Sharp Chula Vista Medical Center, Scripps Mercy Hospital, and the Endoscopy Center of Chula Vista, he conducts procedures across three facilities and consults in English, Spanish, and Tagalog. Maintenance therapy for IBD and GERD often requires proton-pump inhibitors, 5-ASA compounds, and immunomodulators dispensed through local pharmacies such as South Bay Pharmacy, supporting continuous medication adherence between endoscopic follow-ups. The procedural range extends to esophageal dilation for peptic strictures and polypectomy with snare cauterization during screening colonoscopy, performed under moderate sedation at the Endoscopy Center of Chula Vista.