About Molly Thomas, MD, PhD

Molly Thomas, MD PhD is a physician in the Division of Gastroenterology at Massachusetts General Hospital and an Instructor of Medicine at Harvard Medical School. Dr. Thomas cares for patients with a broad range of gastrointestinal problems and specializes in treating immunologic diseases of the gastrointestinal tract including ulcerative colitis, Crohn’s disease, microscopic colitis, eosinophilic esophagitis, celiac disease, and gastrointestinal toxicities resulting from the use of immune checkpoint inhibitor therapy. She performs upper endoscopies as well as diagnostic and screening colonoscopies.

She was born and raised in San Francisco, California and graduated with honors in Biological Sciences from Stanford University. She completed her medical degree at the University of California, San Francisco. There she also earned a PhD in immunology studying the epigenetic regulation of lymphocyte differentiation and effector function. Dr. Thomas completed her residency in internal medicine and fellowship training in gastroenterology at MGH. In addition to being a physician, she is an scientist who researches autoimmune gastrointestinal and liver diseases with an active focus on studying immune toxicities related to checkpoint inhibitor therapy used to treat cancer. 

Departments, Centers, & Programs:

Clinical Interests:



Mass General Gastroenterology
55 Fruit St.
Boston, MA 02114
Phone: 617-726-2426

Medical Education

  • M.D.; Ph.D., UC San Francisco School of Medicine
  • Residency, Massachusetts General Hospital*****
  • Fellowship, Massachusetts General Hospital*****

American Board Certifications

  • Gastroenterology, American Board of Internal Medicine
  • Internal Medicine, American Board of Internal Medicine

Accepted Insurance Plans

Note: This provider may accept more insurance plans than shown; please call the practice to find out if your plan is accepted.

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