An outbreak of the norovirus at a hospital in Cornwall is affecting 11 wards, health bosses say.
Six wards at the Royal Cornwall Hospital in Truro are closed to new admissions and five have bays where patients are being kept isolated.
Visits to all three Royal Cornwall Hospitals Trust sites in Truro, Penzance and Hayle are being restricted to patients who are critically ill.
Urgent surgery and outpatient appointments are going ahead.
Non-urgent surgery is being reviewed on a day-by-day basis, the Royal Cornwall Hospitals Trust said.
Visits are being restricted to the West Cornwall Hospital in Penzance and St Michael's in Hayle to try and prevent the virus spreading to them.
The symptoms of the norovirus infection usually begin around 12 to 48 hours after a person has become infected.
It starts with a sudden onset of nausea and is followed by vomiting and diarrhoea.