Three thousand junior doctors have gone on strike in a row over what they describe as "dangerous" working hours.
15 thousand patients have been hit by the one day strike at over 50 hospitals around the country.
The Irish Medical Organisation is warning that the strike could escalate next week - unless realistic proposals are put forward by the HSE.
Junior doctors say they regularly work shifts of over 24 hours and say they frequently suffer from exhaustion.
Louise Kelly has been talking to patients and striking doctors at the Mater Hospital in Dublin.
The Irish Patients Association says it's not clear how the 15,000 patients affected by todays industrial action will be catered for.
Stephen Mc Mahon from the association says the Minister for Health should intervene.
He spoke to Sinead Spain:
