Marlyn Mayo, M.D., is Professor of Internal Medicine at UT Southwestern Medical Center, and a member of its Division of Digestive and Liver Diseases. She specializes in the diagnosis and management of acute and chronic liver diseases, and has a keen interest in immune-mediated and cholestatic liver diseases such as primary biliary cirrhosis, autoimmune hepatitis, and primary sclerosing cholangitis.

Originally from Syracuse, New York, Dr. Mayo holds a bachelor's degree in psychology from Northwestern University in Evanston, Illinois. She obtained her medical degree from Baylor College of Medicine in Houston, and completed internal medicine residency training at the University of California, Irvine. She then received advanced training through a fellowship program gastroenterology/hepatology at UT Southwestern.

Board certified in internal medicine and gastroenterology, she joined the UT Southwestern faculty in 1996.

Dr. Mayo became interested in primary biliary cirrhosis (PBC) because of her interest in autoimmune diseases. She found it very curious that the body would attack itself. Although she was initially interested in lupus and scleroderma, an attending physician she worked with during her residency inspired her to follow him into hepatology. Dr. Mayo then came to UT Southwestern to do research and work on the largest PBC trial at the time with Burton Combs, M.D., who started the liver unit at UT Southwestern. She had the opportunity to work with many patients as well as do basic lab research on the causes of PBC. 

Later, Dr. Mayo worked with Peter Lipsky, M.D., to conduct research on intrahepatic cholestasis of pregnancy (ICP). She became interested in this disease because it is similar to PBC. Current research is finding some of the genes that cause this disease, which may later help her find causes of PBC. From there, Dr. Mayo started to treat other diseases that relate to pregnancy and liver diseases. 

Currently, Dr. Mayo's research focuses on the pathogenesis of autoimmune liver diseases. The molecular events involved in bile duct damage in primary biliary cirrhosis and development of cryoglobulins in hepatitis C are current areas of investigation. She studies how the T cell receptors and other co-stimulatory molecules on the surface of B and T lymphocytes participate in the genesis and chronic perpetuation of autoimmune diseases. Dr. Mayo also conducts clinical trials in the UT Southwestern General Clinical Research Center investigating new treatments for primary biliary cirrhosis. 

Not only does Dr. Mayo practice medicine, she also teaches it. She finds it fun to be involved in training of fellows and is now the training director for the Division of Digestive and Liver Diseases. All of UT Southwestern’s Division of Digestive and Liver Disease fellows publish papers before they leave, and some may play a role in shifting current standard medical practices. One student research project examined the causes of jaundice in pregnancy and challenges the current paradigm of viral hepatitis testing. Data from this research project suggests that patients should instead be examined by ultrasound for gallstones and treated right away.

In addition, Dr. Mayo has been involved in setting the standards for medical education. These standards are moving away from the concept of competency by numbers to conceptual competency-based evaluation. Fellows are no longer evaluated on the number of procedures they perform, but on milestones that determine a fellow is capable of working at a specialist level. Milestones include scoping with ease and comfort, as well as intake and diagnosis at a specialist level. There is also no set time period to finish their training. If a fellow takes longer to become competent, he or she will not complete their fellowship until ready. As an educator, Dr. Mayo is able to determine some of the milestones fellows must reach.

Most important, Dr. Mayo understands the value of active listening and good communication. To be an effective teacher and physician, she knows she must be able to listen to her students and patients and effectively explain issues to them. “Some patients know their bodies very well, and physicians can figure out their issue if they just listen,” she says.

Dr. Mayo was included in D Magazine's Best Doctors list for 2018.


Medical School
Baylor College of Medicine (1990)
University of California, Irvine (1991), Internal Medicine
University of California, Irvine (1993), Internal Medicine
UT Southwestern Medical Center (1996), Gastroenterology

Research Interest

  • Autoimmune liver diseases
  • Liver Disease in Pregnancy
  • Primary biliary cholangitis
  • primary sclerosing cholangitis


Featured Publications LegendFeatured Publications

Diagnosis and management of autoimmune hepatitis in adults and children: 2019 practice guidance and guidelines from the American Association for the study of liver diseases.
Mack CL, Adams D, Assis DN, Kerkar N, Manns MP, Mayo MJ, Vierling JM, Alsawas M, Murad MH, Czaja AJ, Hepatology 2019 Dec
A Randomized, Controlled, Phase 2 Study of Maralixibat in the Treatment of Itching Associated With Primary Biliary Cholangitis.
Mayo MJ, Pockros PJ, Jones D, Bowlus CL, Levy C, Patanwala I, Bacon B, Luketic V, Vuppalanchi R, Medendorp S, Dorenbaum A, Kennedy C, Novak P, Gu J, Apostol G, Hirschfield GM, Hepatol Commun 2019 Mar 3 3 365-381
Primary Biliary Cholangitis: 2018 Practice Guidance from the American Association for the Study of Liver Diseases.
Lindor KD, Bowlus CL, Boyer J, Levy C, Mayo M, Hepatology 2019 01 69 1 394-419


Featured Books Legend Featured Books

Honors & Awards

  • Education Excellence Award
    UT Southwestern Graduate Medical Education Office (2020)
  • Lyman Bihartz Teaching Award
    Fellow- Nominated Teacher of the Year (2018)
  • D Magazine Best Doctors
    Peer Nominated Award of Excellence in Clinical Care (2015-2019)
  • Independent Investigator Award
    Pfizer Pharmaceuticals (2002)
  • Liver Scholar Award
    American Liver Foundation (1996)
  • Alumni Award in Neurology
    Baylor College of Medicine (1989)

Professional Associations/Affiliations

  • American Association for the Study of Liver Diseases
  • American College of Gastroenterology
  • American Gastroenterological Association
  • Dallas County Medical Society
  • European Association for the Study of Liver Diseases
  • Texas Medical Association