It is understood that seven young people were admitted to Cork University Hospital this morning following the ingestion of a psychoactive substance.
It is feared that the hospitalisations may be related to the drug known as 2CP.
Emergency services were called to a house party on the south side of the city where the party-goers were believed to have ingested 2CP.
In a statement released this afternoon The HSE confirmed that a number of people are being treated, but declined to comment any further.
However, it is understood that two people have recently been released and four are still receiving treatment.
Dr Chris Luke, a consultant in emergency medicine in Cork University Hospital, said that the drug can cause some severe reactions.
"You sometimes see these also with anti-depressants, psychiatric medication, and basically you get a sort of heatstroke, where you get profound muscle damage, you can get rigidity of the muscles, you get seizures, you get heart attacks, and blood pressure," he said.
"Hours later you can get kidney and liver failure."