Prescription tablets have been found among Jelly Tots sweets on a Nestle production line.
Police launched an investigation after workers discovered the pills at the plant near Newcastle, England, last week.
Nestle stressed there had been no risk to the public.
According to reports, the discovery was made in a container of sweets, and Nestle has confirmed the medication was found prior to packaging.
A spokesman said: "We can confirm that there was an incident at our factory in Fawdon, Newcastle, last week.
"The incident was immediately contained, the police were asked to investigate and we are working with them.
"It would not be appropriate for us to make any further comment until they have completed their investigation.
"The incident involved the discovery, in product prior to packing, of a standard prescription tablet, commonly prescribed to both adults and children.
"We can confirm that, due to our rigorous quality procedures and immediate action, the incident was isolated and contained within our control.
"Our customers can be assured that all our products are completely safe."
The company did not order a product recall because it was sure there was no contamination.
More than 400 people work at the plant in Fawdon, which also manufactures popular brands such as Fruit Pastilles and Rolos.