A number of new cases of the Winter Vomiting Bug have been confirmed at hospitals in Sligo and Tallaght.
Sligo General Hospital is not restricting admissions but is asking people to stay away from the hospital unless they are going to outpatient or Accident and Emergency departments, or are visiting a family member.
Staff are requesting that visitors should visit only one patient and should not move around the hospital.
They say children should not be brought in as visitors, and that anyone who has been ill with diarrhoea or vomiting in the last 72 hours should stay away.
A spokesperson for the Eastern Regional Health Authority said people should avoid attending the Accident and Emergency department at Tallaght or any other hospital in the eastern region unless absolutely necessary.
People who believe they have symptoms of the bug should stay away from the hospital, and should not visit any hospital or nursing home until 48 hours after their symptoms have gone.
