President Donald Trump looks out from the Truman Balcony at the White House on October 5, 2020. | Jabin Botsford/The Washington Post via Getty Images

A surprising number of people think the president should take a dangerous drug that has no proven effect against Covid-19.

Much of the United States woke up to the news that President Trump had tested positive for the coronavirus last Friday. Many turned to social media with theories about how Trump was faking it or had been targeted by an assassination plot. The most popular conspiratorial idea, however, was rooted in a familiar hoax: hydroxychloroquine.

Mentions of hydroxychloroquine spiked in the hours and days following the president’s Covid-19 diagnosis, according to data from the media intelligence firm Zignal Labs, which monitors misinformation on social media, traditional media, and other online sources. The majority of these mentions involved people calling