Dr. Theodore Bayless, Hopkins physician who studied lactose intolerance, dies

A physician as well as a professor, Dr. Bayless treated thousands of patients suffering from gastrointestinal disorders.

Dr. Theodore Bayless, a Johns Hopkins professor and physician whose research of lactose intolerance led to innovations in the treatment of that disorder, died of cancer Feb. 10 in Towson. The Mount Washington resident was 87.

Dr. Bayless, originally from Atlantic City, N.J., was the son of David and Fanny Bayless, who ran Bayless Pharmacy, then a well-known pharmacy in Atlantic City. Dr. Bayless worked at the lunch counter during his childhood, and sometimes accompanied his uncle, a doctor, on house calls, said his son, Neal Bayless of New York.


He studied at the University of Pennsylvania and at Bucknell University as an undergraduate. At Bucknell, he met his future wife, Jaye Nides. They married in 1954 and remained married for 64 years, until Dr. Bayless’ death.

Dr. Bayless received his medical degree from the Chicago Medical School and then trained in internal medicine at the Cornell Division of Bellevue Hospital and Memorial Sloan-Kettering Cancer Center in New York.


Dr. Bayless came to the Johns Hopkins School of Medicine in 1964 on a fellowship and was eventually named a professor of medicine. He started his research and clinical work in gastrointestinal diseases and stayed with the field throughout his career.

By studying patients with milk intolerance, “he discovered the enzyme that causes lactose intolerance, an incredibly important discovery,” his nephew, Bob Kravitz, said in an email. That research helped inspire the invention of lactose-hydrolyzed milk and medications that allow people with lactose intolerance — a majority of the world’s adult population — to eat dairy products, said a colleague, Dr. Marshall Bedine.

He also made important contributions to the study of inflammatory bowel disease and Crohn’s disease, identifying patterns in families of the disease’s recurrence. He co-authored 145 peer-reviewed research papers and edited 13 books for practicing physicians and patients.

He was a physician as well as a scientist and teacher. Dr. Bayless treated thousands of patients suffering from gastrointestinal disorders, according to a biography on the Johns Hopkins website.

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“He spent a lot of time with patients, really teasing out lots of details of their condition. He’d use that to form the basis of his recommended treatment,” Dr. Bedine said. He was known to give his home phone number to patients, Dr. Bedine said.

“He was there for people,” said his son Neal Bayless. “He would get calls most nights. He got calls until a couple weeks ago.”

Dr. Bayless became head of the Division of Gastroenterlogy and Hepatology at Johns Hopkins and was director emeritus of the Meyerhoff Inflammatory Bowel Disease Center. In addition, he served as the director of the American Gastroenterological Association section on Immunology, Microbiology and Inflammatory Disorders as well as the national chairman for the The Crohn’s & Colitis Foundation of America.

He received many awards, including a 2015 lifetime achievement award from The Crohn’s & Colitis Foundation of America for his work in the field of inflammatory bowel disease and an award from the Franklin Institute for his work in lactose intolerance. In 2004, he received the Excellence in Teaching Award from the Johns Hopkins Alumni Association.


Along with his wife, Dr. Bayless was an appreciator of the arts, and he regularly attended plays and operas in the Baltimore area. “My mom got him into opera and though he would sometimes take a nap, he became a pretty avid fan as well,” said his son. They belonged to the Lotos Club in New York, a sort of urban country club for academics founded in part by Mark Twain.

In addition to his wife and son, survivors include two other sons, Jeffrey Bayless of Richmond, Va., and Andrew Bayless of Tucson, Ariz.; and four grandchildren.

Services were held Sunday at Baltimore Hebrew Congregation.