Weed preventing COVID-19? That high hope seemed to rise from this headline: "Cannabis May Stop Coronavirus From Infecting People, Study Finds." The headline appeared on an article on that was widely shared on Facebook. But readers should not get too excited.The post was flagged as part of Facebook’s efforts to combat false news and misinformation on its News Feed. (Read more about our partnership with Facebook.)

A preliminary study supported researchers’ theory that certain cannabis extracts could be used as part of a treatment to prevent coronavirus infections. But the study has not been peer reviewed and no testing has yet been done on humans.

"Yes, this is an overstatement," Igor Kovalchuk, the lead researcher of the study, told PolitiFact about the headline. Cannabis isn’t exactly marijuana. Cannabis and marijuana are not exactly the same. Cannabis refers to all products derived from the plant Cannabis sativa. The cannabis plant contains about 540 chemical substances.

Marijuana refers to parts of, or products from, the plant Cannabis sativa that contain substantial amounts of tetrahydrocannabinol (THC). THC is the substance that’s primarily responsible for the effects of marijuana on a person’s mental state. 

Headline partly contradicted by article. The website that published the article is part of Los Angeles-based Merry Jane, which describes itself as a "multi-media and lifestyle company that’s creating the new mainstream culture by connecting cannabis and pop culture."

The article, however, is more nuanced than its headline. The article says that based on the study, "cannabis extracts could work as an ‘adjunct therapy’ in new medical products that could reduce the chances of someone getting COVID-19." 

In other words, despite the headline on the article, the study isn’t saying cannabis alone could prevent infection.