A group of renowned physicians petitioned Columbia University this week to fire television personality Dr. Oz from the school’s faculty, characterizing the celebrity doctor’s brand of medicine as being full of “various quack propositions” and “magical mystery cures.”

In a letter sent to Columbia University, ten prominent physicians questioned Dr. Oz’s medical advice, along with the university’s motivation for keeping him on staff. Oz currently serves as vice chairman of the school’s department of surgery. He reportedly joined the school’s faculty in 1993.

“He’s a quack and a fake and a charlatan,” accused Stanford University’s Dr. Henry Miller, according to the New York Daily News.

“I think I know the motivation at Columbia,” Miller added. “They’re star-struck, and like having on their faculty the best-known doctor in the country. But the fact is that his advice endangers patients, and this doesn’t seem to faze them. Whether they’re hoping Oprah will come and endow a center for homeopathic medicine, I don’t know.”

Letter co-signer Dr. Gilbert Ross, executive director of the American Council on Science and Health, charged Oz of benefitting from the “various quack propositions that he is promulgating on his TV show – magical mystery cures.”

“We find it a shame that he has fled from the ethical and responsible practice of medicine to exploit his television popularity,” Ross said, according to the Daily News.

Columbia University quickly issued a statement in response to the letter.

“Columbia is committed to the principle of academic freedom, and to upholding faculty members’ freedom of expression for statements they make in public discussion,” said Doug Levy, chief communications officer at the school’s Medical Center.

Levy confirmed to USA Today that the school had no plans to take action against Oz.

Oz has come under increasing scrutiny over medical claims he has made on his daytime talk shows The Dr. Oz Show and The Doctors, which together are watched by more than 5 million people a day.

In December, the British Medical Journal published a study claiming that roughly half of the medical advice presented during Oz’s daytime talk shows could not be supported by existing medical evidence.

“Approximately half of the recommendations have either no evidence or are contradicted by the best available evidence,” the study concluded. “Potential conflicts of interest are rarely addressed.”

In June, Oz appeared before the Senate Commerce Subcommittee on Consumer Protection, where he was grilled by chairwoman Sen. Claire McCaskill over his medical recommendations. The doctor defended himself, although he acknowledged he has “made it more difficult for the FTC.”

“If I can just get across the big message that I do personally believe in the items I talk about in my show. I passionately study them,” Oz told the Senate panel. “I recognize that oftentimes they don’t have the scientific muster to present as fact. But, nevertheless, I give my audience the advice I give my family all the time. I give my family these products, specifically the ones you mentioned. I’m comfortable with that part.”