A person who was taken into custody yesterday evening was rushed to hospital with a suspected heroin overdose.
It was not publicly known last night why the person was held in Mayfield Garda Station.
But at some stage in their detention, they were found in an unresponsive state.
The alarm was called, and it is believed that basic first aid was administered to the person as paramedics rushed to help them.
They are then believed to have been rushed to Cork University Hospital.
Initially, there had been rumours the individual had died in custody.
But it soon emerged it was one of the regular checks by station staff on the condition of the prisoner that led to him being discovered unconscious.
Their timely intervention looks likely to have saved their life.