It's a popular trend among teenagers that can cause serious health problems.
The concern is over small magnet balls known as "bucky balls" that many children and teens use to fake piercings.
They put them on their tongue, lip and nose and attach another magnet ball to the other side.
According to one San Diego doctor, many kids take them off to eat and attach them to their braces. And often times, they accidentally swallow the magnets.
Over the course of a few days, kids can end up swallowing several magnets, which can cause intestinal problems.
"So even though you swallowed one a week ago," said Dr. Keith Vaux with Rady Children's Hospital, "it may not have passed because they are so tiny and you may not have noticed it. So then you accidently swallow a second one and it comes down and clamps onto that one and then you have a problem."
According to Dr. Vaux, there have been reports of the magnets getting clumped together in the intestines and causing a blockage.
He says if kids swallow a magnet, they need to let their parents know immediately and get to the doctors quickly to avoid any serious health issues.