A passer-by who went to the assistance of people who had taken a suspected batch of 2CB in Cork has described arriving at the scene - and seeing blood on the walls and carpet.
An 18-year-old remains critically ill in hospital while three others are in a stable condition.
It is understood seven party-goers ingested the psychoactive substance - which is an ecstasy substitute.
The Health Service Executive (HSE) addiction services are issuing a warning about possible contaminated 'party pills' - and are advising people to not consume any unknown substances.
"These drugs can be sold in tablet powder or liquid form and are consumed at parties or clubs for their stimulant, mood altering and in some cases, aphrodisiac effect", the HSE said in a statement.
"However, it is generally reported that these drugs can have serious side effects both from a psychological and physical viewpoint. Such side effects include paranoia, hallucinations (both auditory and visual), gastrointestinal effects and kidney problems".
Gerard Banks arrived at the house where the party was taking place and he describes the scene.
Newstalk.com's southern correspondent and presenter of Lunchtime, Jonathan Healy, is there.
