Four minor injury units in Cornwall are being closed on Friday night. Staff who normally work at the units are being sent instead to the Royal Cornwall Hospital in Truro to help deal with a sickness bug.
Eight wards at the hospital remain closed because of a sickness virus affecting some patients.
The units at Fowey, St Austell, Falmouth and Newquay will close at 1700 GMT and will re-open as normal on Saturday morning.
The Central Cornwall Primary Care Trust has said it will review the situation over the weekend.