Two hospitals in Sussex are working to control an outbreak of the Norovirus winter vomiting bug.
A ward is shut to new admissions at the Princess Royal Hospital
Twelve cases were reported over the weekend at the Royal Sussex County Hospital, in Brighton, and the Princess Royal Hospital, Haywards Heath.
The number of affected patients has since fallen to nine, said Brighton and Sussex University Hospitals NHS Trust.
The bug is extremely infectious. Anyone with symptoms of sickness and diarrhoea should not visit the hospitals.
Balcombe Ward at the Princess Royal Hospital has been closed to all new admissions during the outbreak.
The trust said it was trying to minimise the spread of the Norovirus by limiting the number of relatives visiting patients on the affected wards, and ensuring hand hygiene advice was properly followed.