A stomach flu outbreak, also known as a gastrointestinal outbreak has been declared at the St Marys Memorial Hospital.
The Huron Perth Healthcare Alliance says the hospitals inpatient unit is affected. Gastro causes an infection in the stomach and intestines.
People who visit patients at the hospital are required to follow posted instructions and are asked to limit their interaction to just one patient per visit.
Those with symptoms are being isolated and common areas have been restricted.