When a Facebook post begins with the all-caps phrase “SERIOUS EXCELLENT ADVICE,” there’s a pretty good chance it’s none of those three things. And yet that’s the starter for a nugget of coronavirus misinformation that’s been spreading around the world claiming to offer some sage medical advice during a pandemic.

The post, which has been translated into Portuguese, Turkish, and other languages, more or less reads: “SERIOUS EXCELLENT ADVICE by Japanese doctors treating COVID-19 cases. Everyone should ensure your mouth & throat is moist, never DRY. Take a few sips of water every 15 mins at least. WHY? Even if the virus gets into your mouth … drinking water or other liquids will WASH them down through your esophagus and into the stomach. Once there in your tummy…your stomach ACID will kill all the virus. If you don’t drink enough water more regularly…the virus can enter your windpipes and into the LUNGS. That’s very dangerous.”

It’s alarmist, and it’s untrue. “I think there’s always been this belief that anytime you get something in your system, anything that’s potentially dominating your system, that you can flush it out much like a sewer system,” says Dr. Paul Casey, chief medical officer of Chicago’s Rush University Medical Center. “And unfortunately, that’s just not fact-based or scientific.”

In this first episode of “Misinformation Contagion,” we look at the claims swirling around online about harnessing what’s supposedly the natural enemy of the virus: water.