Four schoolchildren were taken to hospital after they mistook cocaine for sherbet.
Police were called to Broadstone Middle School in Dorset after reports some of the pupils had taken a white powder, mistakenly thinking it was sweets, on January 3.
The students were taken to hospital where they were checked by medical staff before being released.
A spokesman for Dorset Police said: “The children believed the substance was sweets, but it has 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.”
A 32-year-old man from Bournemouth has been arrested on suspicion of drug offences and is currently on police bail until the middle of February pending further inquiries.