Emergency room visits for children swallowing small, lithium batteries have more than doubled in the past 20 years.
That's according to a new study in Pediatrics online.
Researchers say 60-percent of the victims are boys.
When it comes to the button-sized batteries, swallowing is the most common problem that leads to ER treatment.
But kids are also putting the shiny metal batteries in their noses and ears, too.
Researchers say batteries are particularly dangerous for children under five.
And that the increasing number of ER visits show the need for parents to take better precautions.