It was unclear how many children ate the pet treats, but the part-time worker at Upper Frederick elementary school in New Hanover gave them to about 75 students on Thursday, Richard Faidley, the Boyerton Area School District superintendent, said in a statement seen by Reuters.
It was unclear what might have motivated the aide to hand out the pet treats to students. The worker at the school, which is about 30 miles (48 km) northwest of Philadelphia, has been placed on leave pending the results of an investigation, the statement said.
"The treats may have been misrepresented as cookies or crackers," Faidley said in the statement released on Friday.
Faidley could not be reached for comment on Saturday.
"Our research on the product indicates that the treat ingredients would not be harmful to people, with the exception for those individuals with specific food allergies," Faidley's statement said.
One student at the school, Gabriel Moore, told local television station WFMZ that he ate three of the treats.
"She made it look like it was a joke that they were dog treats and then she came around and said, 'No they are cookies. They are fine,'" Gabriel told the station.