Robert F. Kennedy Jr. really doesn’t like fluoride. First he went after it in water, and now he’s going after it in prescription form for children.

The Food and Drug Administration announced Tuesday it will work to remove ingestible products containing the cavity-fighting mineral from the market, ironically, just in time for candy-crazed Halloween.

“The best way to prevent cavities in children is by avoiding excessive sugar intake and good dental hygiene, not by altering a child’s microbiome,” FDA Commissioner Marty Makary says. “When it comes to children, we should err on the side of safety.”

The agency claims ingestible fluoride has been shown to alter the gut microbiome, the tiny bacteria that keep the digestive system healthy. The FDA says there are concerns about how fluoride affects the early development of children.

A news release by the FDA also claims studies have suggested an association between fluoride and thyroid disorders, weight gain, and possibly decreased IQ.

Mr. Makary says the Center for Drug Evaluation and Research will evaluate the evidence regarding the risks of systemic fluoride exposure from FDA-regulated pediatric ingestible fluoride prescription drug products to better inform parents and the medical community on “this emerging area.”

The Department of Health and Human Services plans to release best practices for dental hygiene in children that it considers “feasible, effective, and do not alter gut health.”

Mr. Kennedy says that fluoride is a “dangerous neurotoxin,” linking it to conditions such as arthritis, bone fractures, and thyroid disease. “Ending the use of ingestible fluoride is long overdue,” said Mr. Kennedy. “This decision brings us one step closer to delivering on President Trump’s promise to Make America Healthy Again.”

Mr. Kennedy directed the Centers for Disease Control and Prevention in April to stop recommending fluoridation in drinking water systems nationwide. He also announced the formation of a task force focused on the potential risks of fluoride.

Utah became the first state to ban fluoride in public water, a move Mr. Kennedy hailed as a major victory for health-conscious Americans.