STAFF at Wrexham Maelor Hospital are urging people to think twice before attending the hospital to prevent the spread of noro- virus.
About 20 patients, on five wards, have symptoms that might be caused by norovirus, also known as winter vomiting disease.
The disease is described as a contagious condition, both inside hospitals and in the general community.
To reduce the risk at Wrexham Maelor, where patients are thought to be suffering from the illness, strict controls have been put in place and transfers of patients into and out of affected areas are restricted.
The hospital has also limited the number of beds available for new patients.
Visitors should not attend if they have been suffering from stomach upsets, diarrhoea or vomiting.
Spokesman Andy Scotson said: “While this bug is doing the rounds in the local area, we really would like people to think twice before coming to visit patients in hospital and where possible avoid bringing children to visit, especially where their relatives are on a ward that has been affected by norovirus.
“Not only will that reduce the chances of infection being carried into the hospital, it will help protect visitors from the risk of picking up the illness.”