A 6-month-old girl died from a fatal dose of allergy medicine at a daycare in North Carolina, local media reports.

Harper, the 6-month-old, was given the active ingredient in allergy medicine like Benadryl, called diphenhydramine, a criminal investigation determined.

“She had high doses of Benadryl In her system – that’s basically what killed her,” said Larry Briar, her grandfather.

Children less than 6 years old shouldn’t be given diphenhydramine unless they have a doctor’s note, the medical examiner’s autopsy said.