A four-year-old girl handed out bags of her mother's heroin to other children at a daycare centre believing they were sweets.
Several children who received the packets went to the hospital as a precaution, Delaware police said.
None of the packets were actually opened and all of the kids were released after being examined.
The girl's mother, 30-year-old Ashley Tull of Selbyville, was charged with three counts of child endangerment and maintaining a drug property. She was arraigned Monday and released on $6,000 bond. She did not immediately return a call left at a home listing Tuesday.
The child endangerment counts relate to Tull's three children, who range in age from 11 to 4. As part of her release, Tull was ordered not to have any contact with her children, who are now in the custody of a relative, according to police.
Police say the girl unknowingly brought the heroin to the centre when her mother gave her a different backpack because the girl's regular backpack had been ruined by the family pet. Police say the backpack contained nearly 250 packets of heroin, totaling nearly 4 grams, all labeled "Slam."
Delaware State Police spokesman Master Cpl. Gary Fournier told The News Journal of Wilmington he believes the day care centre, the Hickory Tree Child Care Centre in Selbyville, handled the situation properly, and notified police immediately when it occurred.
A call to the centre was not immediately returned Tuesday morning.
Police say their investigation is ongoing.