Dr. Mark C. Mattar

Dr. Jonathan M. Koff is a gastroenterologist affiliated with Sibley Memorial Hospital and Washington Hospital Center. Dr. Koff practices out of Capital Digestive Care’s Metropolitan Gastroenterology Group, located in Washington, D.C. and Chevy Chase, Md. Dr. Koff has an expertise in esophageal disease and colon cancer detection and screening, in addition to general gastroenterology. Dr. Koff earned his undergraduate degree from Wesleyan University and his medical degree from Boston University School of Medicine. He completed a residency in internal medicine at Walter Reed National Military Medical Center, where he went on to complete a fellowship in gastroenterology. Dr. Koff served in the United States Army for 11 years, working as an internist at the Army clinic in the Pentagon, as a first responder on 9-11 and on a tour in Iraq at the 31st Combat Support Hospital in Mosul. Dr. Koff also went on to direct the Center for Liver Disease and the Inflammatory Bowel Disease Clinic at Walter Reed Army Medical Center, where he served as the director of clinical research in gastroenterology as well. He also completed the first double balloon enteroscopy in the United States Army and in Washington, D.C. Dr. Koff is a member of the American College of Gastroenterology. He is on Sibley Memorial Hospital’s Emergency Room Committee and Internal Medicine Peer Review Committee. Dr. Koff has been named a Top MD by Washingtonian Magazine. Dr. Koff has contributed to various publications and presentation on gastroenterology. Dr. Koff is rated as a Distinguished provider by MediFind in the treatment of Eosinophilic Colitis. His top areas of expertise are Crohn's Disease, Ulcerative Colitis, Eosinophilic Colitis, Endoscopy, and Gastrectomy.

Dr. Kathryn E. Kirk is a gastroenterologist affiliated with Sibley Memorial Hospital, George Washington University Hospital, Washington Hospital Center and the University of Maryland Baltimore Washington Medical Center. She practices out of Capital Digestive Care’s Metropolitan Gastroenterology Group in Washington, D.C., Chevy Chase, Md. and Bethesda, Md. Dr. Kirk has an expertise in gastroesophageal reflux disease, colorectal cancer screening and irritable bowel syndrome. She has special interests in colon cancer screening and prevention, celiac disease and eosinophilic esophagitis. Dr. Kirk earned her undergraduate degree from Princeton University and her medical degree from Weill Medical College of Cornell University. She completed a residency in internal medicine at Beth Israel Medical Center, followed by fellowships in hepatology and gastroenterology at Mount Sinai Hospital. Dr. Kirk is a member of the American College of Gastroenterology, the American Society for Gastrointestinal Endoscopy, the Crohn’s and Colitis Foundation of America and the American Gastroenterological Association. Dr. Kirk has been consistently recognized as a Top Doctor by Washingtonian magazine. Dr. Kirk is rated as a Distinguished provider by MediFind in the treatment of Eosinophilic Colitis. Her top areas of expertise are Crohn's Disease, Ulcerative Colitis, Gastroesophageal Reflux Disease (GERD), and Eosinophilic Colitis.

A Washington-area native, Dr. Erica R. Cohen is a highly-accomplished physician. She is a trained Inflammatory Bowel Disease specialist which gives her unique expertise in Crohn's disease, ulcerative colitis, microscopic colitis, and refractory c. difficile colitis infection. In addition, she treats a wide range of concerns such as celiac disease, colon cancer screening, and diverticular disease. Dr. Cohen is rated as a Distinguished provider by MediFind in the treatment of Eosinophilic Colitis. Her top areas of expertise are Diverticular Disease, Crohn's Disease, Ulcerative Colitis, Viral Gastroenteritis, and Endoscopy.