The HSE is warning drug users to avoid a new batch of dangerous ecstacy-type pills - known as "Double Cross" or "Double Black".
It comes as gardaí investigate the death of 22-year-old Oisin Crawford at a house party in St Johnston .
It is believed officers are looking into whether he had taken the drug or not.
Another man is fighting for his life after taking ill at the party.
The alert comes after the HSE issued warnings last week about green ecstasy pills, called 'Green Apple' and 'Green Rolex', with an apple or Rolex symbol.
Dr Fergal Hickey joined Shaun to discuss the dangers.