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Mon - Fri: 8am - 4pm
Sat and Sun: Closed

meet the doctor
Greg S. Cohen, MD


Dr. Cohen practices General Gastroenterology with additional special focuses on Crohn's Disease,  Ulcerative Colitis, and non surgical treatment of hemorrhoids. Dr. Cohen is originally from Potomac, Maryland. He completed his undergraduate work at Cornell University and medical school at the University of Maryland. Dr. Cohen moved to Chicago in 1998 where he completed his residency at Northwestern followed by a 4 year combined clinical and research GI fellowship under an NIH training grant at the University of Chicago. He has been in practice at Northwestern since 2005.

Dr. Cohen is board certified in Gastroenterology and is a Clinical Associate Professor of Medicine at Northwestern University. He is a fellow of both the American College of Gastroenterology and the American Gastroenterological Association. He is actively involved in teaching medical students as well as GI fellows, and has received multiple teaching awards from the Northwestern University Feinberg School of Medicine. He has published multiple papers and also serves as a peer reviewer.

Dr. Cohen's practice philosophy is simple: he takes care of his patients the way he would want any doctor to take care of him. Appointments are as long as they need to be. Phone calls and electronic messages to the doctor are always returned by the doctor himself, and usually within a few hours. Dr. Cohen is part of the private practice community at Northwestern Memorial Hospital.

To find other Northwestern private practice physicians, click this link.

Dr. Cohen is married with three children and one dog. He spends his free time with his family, building model rockets with his kids, skiing in the winter, and volunteering as camp doctor at his kids' summer camps in the North Woods of Wisconsin.

Click here to read an interview of Dr. Cohen in VoyageChicago.


Areas of Interest:

Celiac Disease, Colon Cancer Screening, Constipation, Crohn's Disease, Diarrhea, Familial Colon Cancer Syndromes, Hemorrhoid Treatment, Inflammatory Bowel Disease, Peptic Ulcer Disease, Rectal Bleeding, Swallowing Disorders, Ulcerative Colitis

Lay press references:

Questions and answers about IBD

Coffee and the GI tract

Runner's diarrhea

Than J, Cohen G: "Colovesical Fistula: An Uncommon Cause of Hematuria and Rectal Bleeding." Case Reports in Gastrointestinal Medicine. 2022; Article ID 1419250, 3 pages.

Cohen G, Shanahan C: "Benign Solitary Cecal Ulcer Syndrome." American Journal of Gastroenterology. 2020;115(3):317.


Cohen G: “Melanosis Coli.” Clinical Gastroenterology and Hepatology. 2020;18(7):e71.

Schenck R, Cohen G, Pezhouh M: “Microscopic colitis: A rare cause of pseudomembranes.” Clinical Gastroenterology and Hepatology. 2019;17(9):e101.

Cohen G, Schenck R: "Cryptosporidium pouchitis." Clinical Gastroenterology and Hepatology. 2017 Jul; 15(7): A27-A28.

Cohen G, Prasad M: “Campylobacter pouchitis mimicking the appearance of Crohn’s Disease.” Case Reports in Gastrointestinal Medicine. 2016, Article ID 5254914, 3 pages, 2016.

Lemmer A, Kia L, Cohen G: “A rare esophageal complication following autologous stem cell transplantation.” Gastroenterology. 2015;148(4):717-718.

Cohen G, Prasad M: “To Band or Not to Band…” Gastroenterology. 2015;148(2):300-301.

Cohen G: “An Unusual Cause of Hematochezia in an Elderly Man.” Gastroenterology. 2014;147(5):e6-e7.

Pekow J, Dougherty U, Huang Y, Gometz E, Nathanson J, Cohen G, Levy S, Kocherginsky M, Venu N, Westerhoff M, Hart J, Noffsinger AE, Hanauer SB, Hurst RD, Fichera A, Joseph LJ, Liu Q, Bissonnette M: “Gene Signature Distinguishes Patients with Chronic Ulcerative Colitis Harboring Remote Neoplastic Lesions.” Inflammatory Bowel Diseases. 2013;19(3):461-70.

Roth MP, Cohen G: “A quarter causing intermittent gastric outlet obstruction.” Gastrointestinal Endoscopy. 2012;75(1):189-190.

Lin CF, Cohen G: “Endoscopic repair of colonic perforation following polypectomy.” American Journal of Gastroenterology. 2009;104(11):2869-70.

Khare S, Mustafi R, Cerda S, Yuan W, Jagadeeswaran S, Dougherty U, Tretiakova M, Samarel A, Cohen G, Wang J, Moore C, Wali R, Holgren C, Joseph L, Fichera A, Chun Li Y, Bissonnette M: “Ursodeoxycholic acid suppresses Cox-2 expression in colon cancer cells: roles of Ras, p38, and CCAAT/Enhancer-Binding Protein.”  Nutrition and Cancer.  2008;60(3):389-400.

Fichera A, Little N, Jagadeeswaran S, Dougherty U, Sehdev A, Mustafi R, Cerda S, Yuan W, Khare S, Tretiakova M, Gong C, Tallerico M, Cohen G, Joseph L, Hart J, Turner JR, Bissonnette M: “Epidermal growth factor receptor signaling is required for microadenoma formation in the mouse azoxymethane model of colonic carcinogenesis.” Cancer Research. 2007;67(2):827-35.

Cohen G, Mustafi R, Chumsangsri A, Little N, Nathanson J, Cerda S, Jagadeeswaran S, Dougherty U, Joseph L, Hart J, Yerian L, Tretiakova M, Yuan W, Obara P, Khare S, Sinicrope F, Fichera A, Boss G, Carroll R, Bissonnette M: “Epidermal Growth Factor Receptor Signaling is Up-Regulated in Human Colonic Aberrant Crypt Foci.” Cancer Research. 2006;66(11):5656-64.

Cerda SR, Mustafi R, Little H, Cohen G, Khare S, Moore C, Majumder P, Bissonnette M:  “Protein kinase C delta inhibits Caco-2 cell proliferation by selective changes in cell cycle and cell death regulators.”  Oncogene. 2006;25:3123-38.

Khare S, Cerda S, Wali RK, von Lintig FC, Tretiakova M, Joseph L, Stoiber D, Cohen G, Nimmagadda K, Hart J, Sitrin MD, Boss GR, Bissonnette M:  “Ursodeoxycholic Acid Inhibits Ras Mutations, Wild Type Ras Activation and Cyclooxygenase-2 Expression in Colon Cancer.”  Cancer Research. 2003;63(13):3517-3523.

Wali R, Khare S, Tretiakova M, Cohen G, Nguyen L, Hart J, Wang J, Wen M, Ramaswamy A, Joseph L, Sitrin M, Brasitus T, Bissonnette M: “Ursodeoxycholic Acid and F6-D3 Inhibit Aberrant Crypt Proliferation in the Rat Azoxymethane Model of Colon Cancer: Roles of Cyclin D1 and E-Cadherin.”  Cancer Epidemiology, Biomarkers & Prevention. 2002;11(12):1653-1662.

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