After seeking advice on health topics from ChatGPT, a 60-year-old man who had a “history of studying nutrition in college” decided to try a health experiment: He would eliminate all chlorine from his diet, which for him meant eliminating even table salt (sodium chloride). His ChatGPT conversations led him to believe that he could replace his sodium chloride with sodium bromide, which he obtained over the Internet.

Three months later, the man showed up at his local emergency room. His neighbor, he said, was trying to poison him. Though extremely thirsty, the man was paranoid about accepting the water that the hospital offered him, telling doctors that he had begun distilling his own water at home and that he was on an extremely restrictive vegetarian diet. He did not mention the sodium bromide or the ChatGPT discussions.

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A century ago, somewhere around 8–10 percent of all psychiatric admissions in the US were caused by bromism. That’s because, then as now, people wanted sedatives to calm their anxieties, to blot out a cruel world, or simply to get a good night’s sleep. Bromine-containing salts—things like potassium bromide—were once drugs of choice for this sort of thing.

Unfortunately, bromide can easily build up in the human body, where too much of it impairs nerve function. This causes a wide variety of problems, including grotesque skin rashes (warning: the link is exactly what it sounds like) and significant mental problems, which are all grouped under the name of “bromism.”

Bromide sedatives vanished from the US market by 1989, after the Food and Drug Administration banned them, and “bromism” as a syndrome is today unfamiliar to many Americans. (Though you can still get it by drinking, as one poor guy did, two to four liters of cola daily [!], if that cola contains “brominated vegetable oil.” Fortunately, the FDA removed brominated vegetable oil from US food products in 2024.)