Many people argue that Mehmet Oz should be treated more like a Kardashian than like a cardiothoracic surgeon. Photograph by Brad Barket/Getty

Mehmet Oz, the heart surgeon whose syndicated television program, “The Dr. Oz Show,” is seen each day by millions of devoted viewers, is arguably the most influential physician in America. For those who have spent time with him, or who watch the show, his popularity isn’t hard to understand: Oz is an eloquent, compassionate, and telegenic representative of a profession whose members often lack those attributes.

Oz also has political skills—you don’t earn the nickname “America’s doctor” without them—as he will undoubtedly demonstrate on his show Thursday afternoon, when he addresses a harsh letter seeking his dismissal from his post as vice-chairman of the department of surgery at Columbia University’s College of Physicians and Surgeons. Last week, a group of ten prominent physicians wrote to the school’s Dean of the Faculties of Health Sciences and Medicine, saying that Oz “has repeatedly shown disdain for science and for evidence-based medicine.” The letter went on to say that by touting unproven remedies for serious ailments, he had “misled and endangered” the public.

Those assertions are frequently confirmed in Oz’s television appearances. Last December, the BMJ (formerly the British Medical Journal) published a study demonstrating that half of Oz’s recommendations either lacked scientific support or were completely contradicted by publicly available data. When Missouri Senator Claire McCaskill, during a Senate hearing on weight-loss pills, asked him about these issues, Oz responded by saying, “I recognize that oftentimes they don’t have the scientific muster to present as fact.” But he continues to act as if he doesn’t care.

Last year, Larry King asked Oz to comment on a Profile I had written about him for this magazine in 2013. Oz said that it was “a thoughtful piece” but that he knew I had a “bias,” which he described as believing that “you need to have very solid scientific data before you say anything.” Oz has no such bias, even though his promotion of a product can affect the lives of people throughout the country. He routinely recommends “miracle” cures for a variety of ailments ranging from obesity to Alzheimer’s disease. Oz has, for example, promoted garcinia cambogia, African mango seed, and green-coffee-bean extract as weight-loss marvels, even though there is no good data to support health claims for any of them.

“You may think that magic is make-believe,” Oz said at the beginning of one typical show. “But this little bean has scientists saying they have found a magic weight-loss cure for every body type. It’s green coffee beans, and, when turned into a supplement, this miracle pill can burn fat fast. This is very exciting. And it’s breaking news.” After Oz discussed green coffee beans on his show, several companies sold tens of millions of dollars worth of the supplement. This phenomenon has become known as the “Oz effect.” The Federal Trade Commission subsequently sued the companies for false and deceptive advertising. In January, the man behind two of the companies agreed to pay back customers nine million dollars.

Columbia has responded to the letter calling for Oz’s dismissal by saying that the university “is committed to the principle of academic freedom and to upholding faculty members' freedom of expression for statements they make in public discussion.” That’s admirable: free speech must be defended vigorously. But to invoke those principles in order to protect the right of one of America’s most powerful doctors to mislead millions of people seems a bit excessive. Oz has already indicated that, on his show Thursday, he will pick apart the qualifications and professional interests of the people who signed the letter. Many have ties to industries and technological innovations, such as genetically modified organisms, that he has long disdained. Fair enough. But changing the subject still won’t change the facts. I have spoken to many of Oz’s colleagues, at Columbia and elsewhere, who feel queasy about Oz remaining a prominent member of the school’s administration.

Many people argue that Oz should be treated more like a Kardashian than like a cardiothoracic surgeon. After all, he’s a television star and his conduct is, unfortunately, common. There have always been hucksters selling false hope to desperate people. It’s an American tradition. But Oz is different precisely because he is so smart, well trained, and influential. How are we to react, then, when he offers his show as a platform for Theresa Caputo, a medium who says she can link us with the dead, or Jeffrey Smith, a former yoga instructor whom Oz considers an expert on genetically modified products?

Oz believes that Western medicine is reductive and that it too often focusses on illness instead of health, with ruinous results. That is hard to dispute. Oz gets it. These days doctors spend less and less time with their patients, but he argues for a deeper connection. (And many studies have shown that people who spend more time with their doctors and nurses have better outcomes.) I do not believe Oz is motivated by money. He was rich before he got his show. I don’t think he is a fraud or a liar, either. But that leaves him somewhere between a cult leader and a talk-show host.

“The currency that I deal in is trust,” he told me when I interviewed him in 2013, “and it is trust that has been given to me by Oprah, and by Columbia University, and by an audience that has watched over six hundred shows.”

Oz refers to Oprah as his mentor, and for good reason: they both are smooth, intelligent, delightful. But Oprah is an entertainer, not a scientist. And at this point, despite his training, his skills, and his many medical accomplishments, so is Oz.