Last night a senior police officer said: "Naturally we are heartened by this news.
"But the message is quite clear - dabbling in any kind of drugs is dicing with death."
The three Largs Academy pupils aged 16, 14 and 13, ended up in hospital.
They were all thought to have swallowed Ecstasy at a party in the town on Sunday.
After exhaustive tests to find out what pills had been taken, the boys were released from Greenock's Inverclyde hospital on Tuesday.
A police source told the Record : "It's still a mystery as to what tablets they did take."
The spokesman added an inquiry was still underway.