A 14 and a 15 year old are believed to taken blue transformer tablets.
Two 16-year-old's were also taken ill.
A 28-year-old man from Tiverton was arrested on suspicion of possession with intent to supply a Class A drug.
He's since been released pending further enquiries.
Police have issued a warning about the dangers of taking drugs.
Concerns for missing Plymouth boy
Jayden West not seen since Wednesday
New cabinet member seeks innovative ways to help rural communities
New rural affairs role at Devon County Council
Increase in prostate referrals leads to backlog
Hospital trust says capacity issue is "temporary"
Murder investigation underway in Exmouth
Third man arrested on suspicion of murder
Cash surplus but long battle ahead for Dartmoor National Park Authority
Reserves are "healthy"
Cash reward for improving hospital waiting times
Derriford hospital awarded £4 million
