US - YouTube’s algorithm promotes fake cancer cures in a number of languages and the site runs adverts for major brands and universities next to misleading videos, a BBC investigation has found.

Searching YouTube across 10 languages, the BBC found more than 80 videos containing health misinformation - mainly bogus cancer cures. Ten of the videos found had more than a million views. Many were accompanied by adverts.

The unproven “cures” often involved consuming specific substances, such as turmeric or baking soda. Juice diets or extreme fasting were also common themes. Some YouTubers advocated drinking donkey’s milk or boiling water. None of the so-called cures offered are clinically proven to treat cancer.

Appearing before the fake cancer cure videos were adverts for well-known brands including Samsung, Heinz and Clinique.

YouTube’s advertising system means that both the Google-owned company and the video makers are making money from the misleading clips. In January, YouTube announced they would be “reducing recommendations of borderline content and content that could misinform users in harmful ways—such as videos promoting a phony miracle cure for a serious illness.”

But the company said the change would initially only affect recommendations of a very small set of videos in the United States, and does not apply in languages other than English.