The videos of people participating in the so-called "boiling water challenge" have become viral.
They show people in parts of the United States hit by the polar vortex and record low temperatures by throwing hot water into the air and observing how the ice crystals become frozen air.
But hospitals warn that the challenge has led participants to suffer serious burns, while the wind blew boiling water on them.
In a statement last week, Loyola University Hospital in Chicago said it had treated eight people who participated in the trick, with varying degrees of burns to the feet, arms and head.
The hospital said the wounded were between 53 and three years old, and included viewers watching another person perform the challenge.
"We've seen eight patients, and we're really surprised at how many people were treating the challenge and unfortunately failing," said Dr. Arthur Sanford, a burn surgeon at Loyola University Medical Center, CBS Chicago reported.
The Burn Treatment Center at the University of Iowa in Iowa City and Hennepin Healthcare in Minneapolis also reported admitting patients with burn injuries caused by the challenge.
"Some of them are parents or adults (who) go out with their children to do it, and the kids get excited and get in the way, and the parents end up throwing water at the children," said Angie Whitley, supervisor of Clinical care in the burn center of the hospital, said at the exit.
"Or, people throw it into the air just when a gust of wind comes, and (the water) catches the wind and blows it back on them, so we see some scald injuries on the face," he added.
In a video posted online in early February, a man in shorts participates in the challenge in front of his home in White Bear Lake, Minnesota. He throws a pot of boiling water in the air, but falls on his leg, scaling it.
The United States strips sank in record cold temperatures when the so-called polar vortex fell in late January, with temperatures in Chicago reaching -45 degrees.
The extreme weather was caused when cold air that spins in a mass that spins over the Arctic was released and headed south towards parts of North America.