Four children were rushed to hospital from their school after mistaking cocaine for sweets.
Emergency services were called to Broadstone Middle School following reports that the youngsters had taken a white powder.
All four were taken to hospital by ambulance and were later discharged after medical staff assessed them as being in good health.
The incident took place on Tuesday January 3, the first day of the school term after the Christmas holiday.
Now an investigation is under way to establish how the substance got into the Dunyeats Road school. The school has around 500 pupils between the ages of nine and 13 and head teacher Dawn Wilks has spoken out in a bid to reassure parents.
She said: “We can confirm that a child at Broadstone Middle School in Poole was found in possession of what was believed to be a drug.
“The children believed the substance to be sweets.
“The police were immediately called and four children taken to hospital to be checked over. They were not found to have any health issues and were discharged the same day.
“Police enquiries are ongoing regarding this incident and as such we are unable to comment further at this time.”
A spokesman for Dorset Police confirmed that all four children involved are pupils at the school but refused to reveal their ages.
He added: “Police were called after reports that four pupils had taken a white powder. The children believed the substance was sweets, but it has now been established it was cocaine. While it was not believed any of the children ingested the powder, they were taken to hospital to be checked over. They were assessed to be in good health and were discharged.”
A spokeswoman for South Western Ambulance added: “We were called to Broadstone Middle School following reports that four pupils had come into contact with an unknown substance. They were treated at the scene before being taken to Poole General Hospital to be checked over.”
A 32-year-old Bournemouth man has been arrested on suspicion of drug offences and is on police bail pending further enquiries.