The Food and Drug Administration is now calling for new warning labels for the prescription drug Lidocaine.
Lidocaine is a gel-like syrup often prescribed to adults to treat mouth pain or throat ulcers.
But now the FDA is warning parents to not use this gel to treat infants while they're teething.
The drug may cause seizures, severe brain injury and heart problems for children.
The FDA is now requiring a warning label to be added to the drug.