Norovirus sparks Royal Cornwall Hospital warning
Visitors have been asked to stay away from the Royal Cornwall Hospital at Treliske after further cases of norovirus.
People are being asked to visit the hospital only if it is "absolutely essential".
The hospital has now had to shut four wards because of the winter vomiting bug.
Patients coming for planned ops, day cases and inpatients, should come in as scheduled.
The hospital will contact them personally if there is a need to change their admission.
Hospital officials said visiting should be restricted to only close family or carers of patients.
People should not visit if they are, or have been, unwell with sickness or diarrhoea.
The symptoms of the infection include a sudden onset of nausea, followed by vomiting and diarrhoea.
Norovirus is contagious from the moment a person begins to feel unwell until at least three days after symptoms have stopped.