Inverness Charleston Academy pupils in substance incident
Two secondary school pupils were taken to hospital on Thursday afternoon after taking an unknown substance.
Highland Council said five pupils of Charleston Academy in Inverness were involved in the incident.
Police Scotland said a 16-year-old male had been arrested and would be the subject of a report to the procurator fiscal.
Pupils have received warnings about misusing substances such as legal highs.
The two pupils were taken to Raigmore Hospital as a precaution and were later allowed to go home.
Extended registration classes and an extended assembly for senior pupils were held on Friday.
Rector Chris O'Neill has written to parents of all the academy's 786 children.
In his letter he said: "Following a substance misuse-related incident at lunchtime yesterday in the vicinity of the Charleston shops an extended registration or assembly was held for all pupils.
"The incident involved five pupils, whose parents have all been directly informed, who had obtained an unknown substance from someone in the community.
"Unfortunately two pupils ended up being taken to hospital, but they have since been discharged and are well."