Evaluates a patient's medical history and educates the patient about digestive health and disease prevention; ... Dr. Mark Birns, MD. Gastroenterology. Rated 4 out of 5 stars, with 19 ratings. 9711 Medical Center Dr. Rockville, MD 20850. ... Dr. Mark Gloger, MD. Gastroenterology. Rated 3.5 out of 5 stars, with 17 ratings. 9711 Medical Center ....