SAN FRANCISCO, July 23 -- Scott Winters was not looking for a second opinion. The Florida pastor had been feeling unwell and, as millions of people do now, he turned to ChatGPT to help make sense of what his body was telling him. What the AI returned, according to a lawsuit filed in San Francisco federal court on Wednesday, was precisely the wrong answer at the worst possible time.

Winters had a pulmonary embolism, a blood clot lodged in the lungs, a condition that can be fatal within hours if untreated. ChatGPT, the lawsuit alleges, did not tell him to seek emergency care. Instead, the chatbot offered what the complaint describes as "tailored medical and spiritual guidance," and over time "gradually reduced warnings to seek professional...