Dr. Iheanyichukwu Aja-Onu, MD, FASGE, FACG

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Get to know Gastroenterologist Dr. Iheanyichukwu Aja-Onu, who serves patients in Oceanside, New York.

Board-certified gastroenterologist, Dr. Aja-Onu, has over three decades of experience in his field. In addition to his affiliation with Mercy Medical Center and St. Catherine of Siena Medical Center, he serves patients at Mount Sinai South Nassau in Oceanside, New York.

Mount Sinai South Nassau is an award-winning, 455-bed, acute care, not-for-profit teaching hospital that provides inpatient, outpatient, home health, restorative, preventive, and emergency medicine services to the area. Prior to his current endeavors, the doctor served as the Chief of Gastroenterology with the SUNY Downstate Medical Center in New York City, New York for over a decade.

His acclaimed career in medicine began in 1986 when he earned his medical degree from the University of Nigeria, Nsukka. Upon relocating to the United States, he went on to complete his internship and residency in internal medicine at St. John’s Episcopal Hospital in New York City, followed by his fellowship in gastroenterology at SUNY Downstate Medical Center. 

The co-author of many papers and publications, Dr. Aja-Onu is board-certified in both internal medicine and gastroenterology by the American Board of Internal Medicine – a physician-led, non-profit, independent evaluation organization driven by doctors who want to achieve higher standards for better care in a rapidly changing world. Additionally, he is a Fellow of the American Society for Gastrointestinal Endoscopy and a Fellow of the American College of Gastroenterology. 

Gastroenterology is the branch of medicine focused on the digestive system and its disorders. A gastroenterologist is a physician who has extensive training in the diagnosis and treatment of disorders related to the esophagus, stomach, small intestines, colon, liver, pancreas, and biliary system. 

Outside of the office, Dr. Aja-Onu enjoys traveling.

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