Three Chicago-area nursery employees have been arrested for allegedly giving a group of toddlers melatonin-laced gummy bears before nap time.
Kristen Lauletta, 32, Jessica Heyse, 19, and Ashley Helfenbein, 25, admitted to distributing the sleep supplement to calm the children down, police say.
Officials said the aides are accused of child endangerment and battery.
The women told police they did not think it was inappropriate since the drug is an over-the-counter sleep aid.
A Kiddie Junction Daycare Center manager said employees had been distributing the melatonin gummy bears to the 12 student class without parentel consent, according to police.
Melatonin is a naturally produced sleep hormone that helps regulate sleep. Availability of synthetic supplements of the hormone vary by country.
While it can be purchased over-the-counter in the US, a doctor must prescribe the supplement in the UK.
It is typically given to people to help create natural sleep cycles and is considered a common sleep medication.
Giving the supplement to children without parent consent is “a very inappropriate and potentially dangerous act”, neurologist Anna Ivanenko told the Chicago Tribune newspaper.
Authorities said parents of children at the childcare centre have since been informed about the incident.
The investigation is ongoing and the three workers are due to appear in court on 4 April.