A viral coronavirus rumor says taking ibuprofen, which is marketed by GlaxoSmithKline as Advil, could make COVID-19 symptoms worse. The message is spreading through text messages and over Twitter, and it claims to be coming from a Vienna laboratory studying COVID-19.

The problem is: there isn’t any evidence that it’s true. There hasn’t been enough research on ibuprofen in COVID-19 patients to determine whether it is actually harmful. An alternative is acetaminophen, which is marketed by Johnson & Johnson as Tylenol. But not everyone can take it because it can make some liver conditions worse.

“Vast majority of people who died had ibuprofen / Advil in their system so do not take it!!” the message reads. “Those who recovered did not take ibuprofen so if you have symptoms, take Paracetamol only!!! Looks like this virus thrives on ibuprofen so don’t do it and tell everyone you can!!!”

Just got this message sent to me from a friend. I have no idea if it's true or accurate. Maybe if we retweet it and pass it around we can get some comments and possibly some clarity. Or maybe it was released by the makers of Tylenol. pic.twitter.com/uFEncIQlZB — Mark Minervini (@markminervini) March 26, 2020

The telltale signs of misinformation are everywhere in the Advil rumor. Many of the messages claim to be coming from someone’s friend or sister who is a nurse at New York University. She seems to have firsthand information about the mysterious Vienna laboratory. The vague attribution makes the information difficult to track. The message also ends with a plea: tell everyone you know! Pass it on! This type of urgent request exploits the need for concrete information and the desire we have to protect one another.

Like most effective misinformation, the message mixes bits of truth with outright lies. For instance, France’s health minister tweeted out a warning that “taking anti-inflammatory drugs (ibuprofen, cortisone, ...) could be a factor in worsening the infection,” wrote Stephanie M. Lee from BuzzFeed.

The warning echoed a letter written to The Lancet, a medical journal, on March 11th. There, researchers claimed that taking certain drugs — including ibuprofen — could make people more susceptible to the virus.

But experts refuted these claims. Michele Barry, director of the Center for Innovation in Global Health at Stanford University, told The New York Times that there was simply no data to back them up. Garret FitzGerald from the University of Pennsylvania’s Perelman School of Medicine, told the Times, “It’s all anecdote, and fake news off the anecdotes. That’s the world we are living in.”

The rumor gained enough traction, however, that GlaxoSmithKline issued a statement refuting the claims. The statement now pops up if you go to the website for Advil. “We understand the use of steroids and non-steroidal anti-inflammatory (NSAIDs) products, including ibuprofen, for the alleviation of COVID-19 symptoms has come into question,” the statement reads. “As a leader in the OTC pain category, GSK Consumer Healthcare is not aware of any scientific evidence that directly links worse outcomes in patients suffering from COVID-19 infection with the use of ibuprofen or other anti-inflammatories.”

The World Health Organization (WHO) told The Verge that it is not aware of any studies showing ibuprofen could be dangerous for COVID-19 patients. “We are consulting with physicians treating COVID-19 patients and are not aware of reports of any negative effects of ibuprofen, beyond the usual known side effects that limit its use in certain populations,” a WHO spokesperson said in an emailed statement. “Based on currently available information, WHO does not recommend against the use of ibuprofen.”