Google’s AI Overviews cite YouTube more often than any medical website when answering health-related searches, according to a German study that raises concerns about the reliability of information shown to billions of users.
Researchers analysed more than 50,000 health queries made in Germany and found that YouTube accounted for 4.43% of all citations, making it the single most referenced source in AI Overviews. No hospital network, government health body or medical association came close. YouTube is owned by Google, whose AI summaries appear at the top of search results and are viewed by about 2bn people each month.
The researchers warned this matters because YouTube is not a medical publisher and hosts content from both qualified professionals and untrained influencers. While Google said its system surfaces high-quality sources and noted that many cited YouTube videos come from medical channels, the study found those videos made up less than 1% of all YouTube links used.
Experts say the findings suggest the risks of misleading health information in AI Overviews are structural, with visibility and popularity often outweighing medical authority.
