Beaumont Hospital in Dublin has asked the public not to attend its Emergency Department unless it is absolutely necessary is it tries to contain an outbreak of the Winter Vomiting Bug.
In a statement, the hospital said it was urging the public who have the symptoms not to attend the hospital, but to contact their GP if they have any serious concerns.
The highly infectious virus causes bouts of violent vomiting and diarrhoea and the whole episode can typically last for up to 60 hours. No medical treatment is normally needed, but people infected need to ensure they do not become dehydrated.
The bug is also causing problems for hospitals in Naas and Navan, the statement said.
Beaumont is already dealing with an outbreak of the virus and said a number of people with the symptoms had come directly to the Emergency Department, resulting in cross infection of patients and staff there.
"Any visitor who cannot postpone his or her visit must wash their hands before and after visiting and use the hand gels provided," a spokesman emphasised yesterday. "They should visit only one patient and go directly to and from that patient. No children or babies are being admitted."
The spokesman added: "We don't want visitors picking this virus up and bringing it to home for Christmas. Nor do we want more people bringing it in with them and adding to our difficulties. So we are also asking the public, please, if you have had a tummy upset involving the symptoms of this virus, do not visit the hospital for at least 48 hours after the last episode."