Long Island Pediatric Gastroenterology

Long Island Pediatric Gastroenterology is a family-focused practice led by Dr. Mark Lowenheim, an award-winning physician with over 20 years of experience.

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What does a pediatric gastroenterologist treat?

Gastroesophageal reflux (GER), peptic ulcers, H. pylori, celiac disease, Crohn’s disease, ulcerative colitis, Hirschsprung’s disease, cyclic vomiting, polyps, gallstones, hepatitis, biliary atresia, jaundice, pancreatitis, lactose malabsorption, failure to thrive and other common and rare disorders.

family-focused care in a friendly environment.

About LIPG

LIPG was created in 2010 by Dr. Mark Lowenheim, a board-certified pediatric gastroenterologist to offer family-focused care in a friendly environment.

Dr. Lowenheim has been practicing medicine on Long Island since 1991. Dr. Lowenheim was the first hospital-based pediatric gastroenterologist in Suffolk County to perform diagnostic procedures such as upper and lower endoscopies in children. He has been recognized as a Top doctor in the NY metro area by Castle Connolly and Newsday.

Dr. Lowenheim is an accredited member of NASPGHAN, the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition.

LIPG offers a unique opportunity for transition support to adult care for young adults with special healthcare needs, as recognized and formalized in routine statements by the American Academy of Pediatrics and the Academy of Family Physicians.


LIPG offers comprehensive outpatient and inpatient services, as well as state of the art diagnostic procedures including:

Endoscopy; Esophageal PH monitoring; and Capsule Endoscopy. Procedures are performed in an accredited abmbulatory Endoscopy facility as well as in St. Charles and Mather Hospitals with board-certified anesthesiologists.

Procedure Information

Healthy Living

Feeding a child can be quite a challenge. Developing and maintaining healthy eating choices is a lifelong endeavor. The United States Department of Agriculture (USDA) has developed MyPyramid guidelines to be used in preparing meals and snacks for all ages greater than 1 year of age. Good and bad nutrition habits begin at home. Individual food preferences and hectic schedules often leave a parent wondering what to do at mealtime. High calorie, highly processed convenience foods are often an easy option. Although many things influence what children eat, adults are still the most important role models when developing healthy eating and lifestyle hebits. This is intended to assist children, adolescents, and families practice healthy eating behaviors and gain more knowledge for optimal nutrition.

What our Patients are saying


I have been going to Dr Lowenheim for 8 years. He has helped me to be comfortable with my disease and has always been informative and supportive.

Bryan, Nesconset

Dr Lowenheim’s expertise, compassion, and impeccablel bedside manner made accepting my diagnosis of celiac disease at age 15 manageable. Now that I live away at college and feel well and symptom free, I want to extend my gratitude to my extraordinary doctor. Thank you Dr Lowenheim.

– Danielle, Farmingville

Working with Dr Lowenheim is a great experience. He is very attentive and you can tell he really cares about his patients on a personal level!

– Jennifer, Hamtpon Bays

The compassionate care provided by Dr Lowenheim in every situation is second only to the comforting reassurance his expert guidance offers to both his patients and their families. I will always put my trust in Dr Lowenheim and know that in return I will be getting the best possible care from this wonderful man.

– Courtney, South Setauket