Mark Christopher Mattar, MD| Gastroenterology | MedStar Health

Mark Christopher Mattar, MD
Provider is directly employed by MedStar Health

4.4 out of 5 (247 reviews)

Specialities: Gastroenterology

Languages: Spanish, Arabic, English


About me

Dr. Mattar is the Quality Improvement Officer for the Division of Gastroenterology.

As the director of the IBD Center he has expertise in diagnosing and treating inflammatory bowel diseases (IBD)Crohn's disease, colitis, and celiac disease. Dr. Mattar has a particular interest in IBD therapeutics and IBD and colorectal cancer prevention. He is active in clinical research and medical education for trainees, the community, and patients.
Dr. Mattar sees patients in his gastroenterology practice at MedStar Georgetown University Hospital. He embraces a team approach to patient care within the IBD Center at MedStar Georgetown as part of a multidisciplinary treatment team that includes dietitians and other key providers. He is also active in clinical trials for IBD and performs fecal microbiota transplantation for recurrent and refractory C. difficile infection.

Dr. Mattar teaches at MedStar Georgetown University Hospital as Associate Professor of Medicine, and is the director of the Fellowship Training Program in Gastroenterology. He is also an active member of the mission committee of the Crohn's and Colitis Foundation, D.C. Metro chapter; the ACG Training Committee and the Patient Education National Scientific Advisory Committee for the Crohn’s and Colitis Foundation. In 2014, Dr. Mattar was recognized by the American Gastroenterological Association's Bridges to Excellence Program for his commitment to providing comprehensive quality care for patients with IBD.

Dr. Mattar enjoys family time with his wife and son, including fishing in local ponds and creeks. He especially enjoys exploring the Washington museums and playgrounds with his young son. He also enjoys checking out the local cafes and creating his own latte art. 

Patients and practitioners can connect with Dr. Mattar on Twitter (@gastrodocmattar) and follow his tweets on new developments in gastroenterology.

The mission of the training program he directs states, "To create an environment where compassionate medical trainees can learn to provide exceptional quality care to the patients we serve." He prides himself in treated his patients as he would his own family.


Clinical areas of focus

  • Anal Fissure
  • Colonoscopy
  • Diarrhea
  • Rectal Bleeding
  • Rectal Pain
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Conditions and procedures

Conditions I treat

  • Anal Fissure
  • Anal Fistula
  • Bright Red Blood Per Rectum
  • Celiac Disease
  • Clostridium Difficile
  • Colitis
  • Collagenous Colitis
  • Colon Stricture
  • Colonic Polyps
  • Crohns Disease
  • Diarrhea
  • Gastroenteritis
  • Ileitis
  • Inflammatory Bowel Disease
  • Iron Deficiency Anemia
  • Irritable Bowel Syndrome
  • Ischemic Colitis
  • Lymphocytic Colitis
  • Microscopic Colitis
  • Proctitis
  • Rectal Bleeding
  • Rectal Pain
  • Small Bowel Stricture
  • Ulceration Of Intestine
  • Ulcerative Colitis
  • Ulcerative Proctitis
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Procedures I perform

  • Biologic Therapy For Gastrointestinal Diseases
  • Colon Polypectomy
  • Colonoscopy
  • Early Detection Of Cancer
  • Endoscopic Mucosal Resection Of Large Colon Polyps
  • Esophagogastroduodenoscopy Egd
  • Fecal Transplant
  • Gastrointestinal Gi Cancer Screening
  • Ileoscopy
  • Proctosigmoidoscopy
  • Sigmoidoscopy
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Practice locations

Distance from Change LocationEnter your Location

3800 Reservoir Road Northwest
Washington, DC, 20007


Fax 877-303-1462

Get Directions

miles away

Fax 877-303-1462


MedStar Medical Group accepts most major health insurance plans. If you are uncertain as to whether your individual health insurance plan is accepted at MedStar Medical Group, please call your insurance company.

  • List of insurance plans we accept
    • Aetna Elect Choice/ EPO (Aetna Health Fund) Innovation Health: Network Only Plus
    • Aetna Quality Point of Service (POS)
    • Aetna USAccess (POS)
    • Aetna Student Health Insurance
    • Aetna Medicare Advantage HMO & PPO Plans
    • CFBCBS BlueChoice HMO
    • CFBCBS Blue Choice Opt Out Plus Open Access (POS)
    • CFBCBS Maryland Point of Service Plan (MPOS)
    • CFBCBS Federal Employee Program (Std. & Basic PPO)
    • CFBCBS Maryland Indemnity or PPO
    • CFBCBS (NCA) Indemnity
    • CIGNA HMO & Network (HMO)
    • CIGNA POS/Network POS
    • Great-West Healthcare POS/CIGNA
    • CIGNA Indemnity
    • Coventry Health Care of Virginia
    • Coventry of Delaware HMO/PPO
    • First Health PPO
    • Tricare Prime
    • Tricare Standard
    • Tricare Extra (Indemnity)
    • Tricare for Life (Medicare Supplemental Plan)
    • MedStar Family Choice - Maryland Health Choice
    • MedStar Select (MedStar Associates' Plan)
    • MedStar Medicare Choice
    • United Healthcare Select HMO - EPO/NPP
    • United Healthcare Select Plus (POS)
    • United Healthcare Choice Plus
    • United Student Resources
    • M.D. IPA (HMO)
    • M.D. IPA Preferred (POS)
    • Optimum Choice Preferred (POS) & OCI Direct (HMO)
    • Mamsi Life & Health (Indem./PPO)
    • Aetna Worker's Compensation Network
    • Coventry Health Care National Network PPO
    • Private Health Care Systems (PHCS) (PPO)
    • United Healthcare Options (PPO) (includes Empire PPO, GEHA, Compass Rose)
    • OneNet PPO, Inc.
    • United Healthcare Choice
    • United Healthcare Core Essential (HMO)
    • Optimum Choice
    • United Healthcare Navigate
    • United Healthcare Compass (HMO)
    • CIGNA HMO Open Access (OA)
    • Network OA
    • POS OA & OA Plus
    • PPO and PPO Plus
    • Choice Fund PPO
    • CFBSBC Blue Preferred PPO
    • HealthyBlue PPO
    • CFBCBS Blue Choice Opt Out Open Access
    • BlueChoice Open Access
    • Blue Choice Advantage & Healthy Blue (HMO, POS)
    • Aetna Traditional Choice (PPO)
    • Innovation Health: Indemnity
    • Aetna Open Choice (PPO)
    • Innovation Health: PPO
    • Aetna Managed Choice (POS)
    • Innovation Health: POS Plus
    • Aetna Elect Choice/ Open Access (POS)
    • Innovation Health: Open Network Only Plus
    • Aetna HMO-Open Access/Select OA/HealthFund/Health Network Option OA
    • Innovation Health: POS
    • Open HMO
    • Opoen HMO Option
    • Open EPO Plus
    • Aetna Managed Choice Open Access (POS)
    • Choice POS & Choice POS II
    • Innovation Health: Open POS Plus
    • Open POS II
    • Aetna HMO
    • Select HMO/HealthFund/Health Network
    • Aetna Innovations: HMO & EPO Plus



Board Certification: American Board of Internal Medicine, Gastroenterology

Fellowship Program: MedStar Georgetown University Hospital (2010)

Residency Program: Olive View - UCLA Medical Center (2007)

Medical School: Virginia Commonwealth University (2004)


  • Washingtonian Top Doctor Award, 2020 Fellow, American Gastroenterology Association, 2020 Fellow, American College of Gastroenterology, 2018 Gastroenterology Fellows Award for Excellence in Teaching, 2015 American Gastroenterological Association's Bridges to Excellence Program, 2014 Commitment to Patient Care, VA Medical Center, 2012

News and publications

Ratings and reviews

  • Provider explained things understandably

  • Provider listened carefully

  • Provider gave easy to understand instructions

  • Provider knew medical history

  • Provider showed respect

  • Provider spent enough time with patient

  • Sep 28, 2021

    Dr. Mattar was excellent - listened to my concerns, empathetic, outstanding care.

  • Jul 28, 2021

    While trying to engage (asking questions, providing additional detail on the current medical situation, etc) with Dr. Mattar regarding symptoms, medical history, and his evaluation Dr. Mattar stated that I was "creating roadblocks" and walked out of the exam room saying the exam is over. While Dr. Mattar's medical knowledge may be significant, his manner in dealing with patients is not acceptable. I wanted over 3.5 weeks for an appointment with him at the very least I wanted was to be fully heard and have my questions answered. Eventually, Dr. Mattar came back into the room after my request to the clinic administrator, but I am incredibly disappointed in Dr. Mattar's lack of professionalism and empathy for a patient in need of answers and treatment.

  • Jul 13, 2021

    I will say that given my need for an appointment 2 months ago it is hard to say - I wish I had just been able to see a doctor sooner.