Alexander J Greenstein

Alexander J Greenstein, MD

  • ASSISTANT PROFESSOR | Population Health Science and Policy



Dr. Alexander J Greenstein specializes in minimally invasive Ulcerative Colitis, Crohn's and Gastrointestinal surgery. Prior to joining our faculty, Dr. Greenstein completed a surgical residency at Mount Sinai Hospital and a fellowship in Minimally Invasive Surgery at the Oregon Health and Sciences University in Portland, Oregon. In addition, Dr. Greenstein completed a residency in General Preventative Medicine and attained a Masters in Public Health at The Mount Sinai Medical School. Dr. Greenstein graduated from Cornell Medical College (NY, NY) Alpha Omega Alpha after completing his bachelor’s degree in Economics Cum Laude with distinction at Yale University (New Haven, CT). Dr. Greenstein is certified by the American Board of Surgery and is a Fellow of the American College of Surgeons (FACS). He has first or co-authored over 45 peer reviewed manuscripts and has presented his work at both regional and national surgical meetings. Additional research engagements include experiences at the National Institute of Mental Health, the Memorial Sloan Kettering Medical Center and the Brazilian Ministry of Health. He is a recipient of the David A. Dreiling Award for Scholarly Excellence from the Mount Sinai Department of Surgery. Dr. Greenstein is an active member of multiple surgical societies (ACS, SSAT, SAGES) and has editorial responsibilities at several journals. His research focuses on advances and techniques in GI surgery for Crohn’s and Ulcerative Colitis and he also has research interest in health disparities, preventive medicine and the role of surgery within the public health sphere. Dr. Greenstein discusses Inflammatory Bowel Disease in the New York Daily News in The Daily Checkup. Watch Dr. Greenstein perform a Minimally Invasive Subtotal Colectomy and J-Pouch for Ulcerative Colitis and a Laparoscopic Ileocolic Resection for Crohn’s Disease. In this nationally presented video, Dr. Greenstein performs emergency surgery for Perforated Crohn’s Disease during Pregnancy Watch Dr. Greenstein's patient tell her story about Ulcerative Colitis on EverydayHealth. Read about Dr. Greenstein's patient with appendicitis during pregnancy on ABC News. See more at:


American Board of Surgery

Clinical Focus


BA, Yale University

MD, Cornell University Medical College

MPH, Mount Sinai School of Public Health

Residency, Surgery, New York Presbyterian - Weill Cornell Medical Center

Residency, Preventive Medicine, Mount Sinai Hospital

Residency, General Surgery, Mount Sinai Hospital

Fellowship, Laparoscopic Surgery, Oregon Health Sciences University