Robert F. Kennedy Jr. has been unflinching in his attacks on the Food and Drug Administration in recent weeks, saying he wants to fire agency experts who have taken action against treatments that have sometimes harmed people or that teeter on the fringe of accepted health care practice.

How much influence Kennedy will have in President-elect Donald Trump’s next administration remains unclear, with some suggesting that he could act as a White House czar for policy over several federal health agencies. Trump has voiced support for Kennedy in recent weeks, saying he will let him “go wild on health.” In his acceptance speech, Trump reiterated his support for Kennedy’s involvement on health matters.

Some of Kennedy’s priorities are relatively standard, such as focusing on the health effects associated with ultraprocessed foods. Yet others threaten to undermine FDA authority to rein in inappropriate medical treatments or to warn about products that can damage the public health.

A spokesperson for Kennedy did not respond to interview requests.

Days before the election, in a post on social platform X that has received 6.4 million views, Kennedy threatened to fire FDA employees who have waged a “war on public health.” He listed some of the products that he claimed the FDA had subjected to “aggressive suppression,” including ivermectin, raw milk and vitamins, as well as therapies involving stem cells and hyperbaric oxygen.

Some items that he singled out had become flash points for conservative voters during the coronavirus pandemic, including ivermectin, which was found to be an ineffective treatment against COVID.

Dr. Robert Califf, the current FDA commissioner who spoke frequently about the dangers of misinformation in the COVID pandemic, said at an event Tuesday that he was aware that experts were not always right — but he worried about them being broadly ignored.

“Not having experts, I think historically, in every society, has been a case for demise of that society,” Califf said.

He also noted that leadership above the FDA — including the Health and Human Services Department — very rarely interferes with scientific decisions at the agency. Yet, “it’s totally within the law for the president or the HHS secretary to overrule the entire FDA,” he said.

Here is a look at some of the items raised by Kennedy and the actions the agency has taken:

Raw milk

Drinking raw milk has always been risky, according to the FDA and the Centers for Disease Control and Prevention. It is regularly associated with outbreaks of illnesses from a long list of bacteria, which includes a strain of E. coli that can cause kidney failure and death.

The bird flu outbreak among dairy cows has heightened the risk to public health, said Meghan Davis, an associate professor at Johns Hopkins University who studies infectious diseases affecting animals and humans. Since the outbreak was first detected in March, the virus, known as H5N1, has spread to nearly 500 herds in 15 states, according to data from the U.S. Department of Agriculture. Raw milk contains high levels of the virus, which can also infect people.

Recent studies by the FDA and the Department of Agriculture have found that pasteurization effectively renders the virus inactive.

Promoting consumption of raw milk — or silencing the FDA from warning about its risks — is “probably a bad idea,” in the middle of a bird flu outbreak, said Dr. Georges C. Benjamin, executive director of the American Public Health Association.

Doing so “would be fine until he gets his first bacterial outbreak in the population of kids drinking raw milk and someone dies because he encouraged people to drink raw milk,” Benjamin said.

There is no test to screen milk for the H5N1 strain in the current outbreak, and not all cows are showing symptoms. Also, the milk is often pooled from numerous cows, so only one cow needs to be sick to introduce contamination.

Proponents of raw milk say it has more beneficial enzymes and diverse probiotics than pasteurized milk and that its consumption is associated with lower rates of asthma and allergies.

Davis said she was concerned that an increase in raw milk consumption could make it easier for the H5N1 virus to adapt and become more severe or transmissible among humans. On Thursday, the CDC released a study showing that some farmworkers carried antibodies to the strain but were not aware that they had been infected.

“This is a virus that has pandemic potential,” Davis said.

Hydroxychloroquine

Early in the pandemic, under pressure from Trump, the FDA issued an emergency use authorization for hydroxychloroquine, a drug used to treat malaria. The agency noted in March 2020 that the drug had been shown in a lab to prevent growth of the coronavirus and that some patients who took it reported improving.

The authorization did not last long. On June 15, the FDA revoked it after a study of 821 people found a lack of effectiveness. The drug also carried serious side effects, including one that disrupted the electrical activity of the heart. The agency concluded that the potential benefits did not outweigh the risks.

In doing so, the FDA showed flexibility in a time of crisis and pulled back when important information came to the fore, said Dr. Ashish Jha, a former Biden White House adviser on the COVID pandemic and the dean of the Brown University School of Public Health.

“That is exactly what you would want the agency to,” he said.

Further studies also found that hydroxychloroquine did not work against COVID, and one large analysis found that people who took it had an elevated risk of death.

Chelation

Kennedy has a history of promoting the possible benefits of chelation, which is an accepted therapy for removing heavy metals from the blood after a serious exposure but not for treating autism.

A blog entry posted by the Children’s Health Defense, a nonprofit founded by Kennedy, claims that “many cases of autism” are actually cases of mercury poisoning brought on by a preservative found in some vaccines. The post, which says it was written in 2000 and posted in 2017, went on to note the promise of chelating agents — chemicals that remove toxic metals from the body — as a potential treatment for autism. A 2015 book edited by Kennedy that focused on widely debunked theories about vaccines and autism notes “evidence of chelation’s benefits” from a handful of small studies.

Doctors do use chelating agents to treat some conditions, like lead poisoning, said Dr. Jeffrey Brent, a toxicologist at the University of Colorado School of Medicine. But he said he doubted that “any legitimate physician” believed that chelation was an appropriate treatment for autism.

Chelation can also be dangerous. A 5-year-old boy died in 2005 from cardiac arrest after a doctor in western Pennsylvania tried to treat his autism with chelation.

“It was a huge problem, and there are people out there that are pushing it,” Brent said. “I’m sure they feel emboldened right now.”

Stem cells

Stem cell treatments have generated excitement in the medical field in recent years. Studies have shown promise in treatments for Type 1 diabetes and macular degeneration. One recently approved therapy combines gene editing and a stem cell treatment for sickle cell disease. Yet amid the hope for revolutionary treatments, rogue clinics have promoted cures that were not approved by the FDA for myriad ailments.

Given the context of Kennedy’s post on X, he appeared to be referring to stem cell clinics that the FDA had targeted for enforcement, said Paul Knoepfler, a professor of cell biology and human anatomy at the University of California, Davis, who tracks questionable stem cell treatments.

Dr. Scott Gottlieb, who was appointed by Trump to lead the FDA during his first term, summarized the problem in 2017, saying that some “unscrupulous actors who have seized on the clinical promise,” of advances in the field were selling “unproven and, in some cases, dangerously dubious products.”

“In such an environment, a select few, often motivated by greed without regard to responsible patient care, are able to promote unproven, clearly illegal and often expensive treatments that offer little hope and, even worse, may pose significant risks to the health and safety of vulnerable patients,” Gottlieb wrote in a statement.

In 2017, Stanford University researchers reported that people who had gone to one stem cell clinic in Florida for eye procedures left with considerable loss of sight, apparently caused by the stem cell infusions.

The next year, the FDA filed two permanent injunctions against stem cell clinics in California and Florida that “have continued to disregard the law and, more importantly, patient safety,” Gottlieb said in a statement at the time.

The two companies sued the FDA and lost their cases at the appellate court level.

A three-judge panel of the U.S. Court of Appeals for the 9th Circuit upheld the FDA’s action in a decision on Sept. 27 of this year, aligning with a Florida judge’s ruling in 2019 that protected the agency’s authority to crack down on a stem cell provider that it had deemed unscrupulous.

In the California case, judges concluded that the FDA had correctly exercised its authority to oversee such treatments.

Given Kennedy’s potential influence in the new administration, he may be able to change the FDA’s direction in such cases, Knoepfler said.