Visiting hours at Beaumont hospital have been restricted due to an outbreak of vomiting and diarrhoea over the past week.
According to a statement released by the hospital tonight approximately 25 patients have been diagnosed with these symptoms.
"As we are just entering the winter months it is extremely important that we take all possible steps to contain this infection as quickly as possible," the hospital said.
The statement continued: "To this end we are only allowing one visitor per patient at any given time and absolutely no visits by children.
"Visiting hours (1pm to 4 pm and 5.30pm to 8.30pm) are being rigidly adhered to and we are asking visitors not to visit more than one ward.
"We are also urging anyone who has had these symptoms recently or is otherwise feeling unwell to refrain from visiting at all, except in the case of a genuine medical emergency".
Patients with appointments are advised to proceed as per existing arrangements.