Friends and relatives of patients at Gloucestershire Royal Hospital have been told not to visit their loved ones.
An outbreak of a diarrhoea and vomiting illness has hit both Gloucestershire Royal and Cheltenham General hospitals.
Bosses at the hospitals have said the restriction is just a precaution to prevent the spread of the illness.
Experts say the illness is usually over within 48 hours, but is highly infectious, which is why bosses need to limit the number of people moving in and out of wards.
Anyone suffering from the illness at home should keep hydrated, maintain high standards of personal hygiene and hand washing.
Patients who are feeling unwell with the bug are being asked not to attend hospital emergency departments.
Anyone with questions can get in touch with NHS Direct by calling 0800 45 46 47.
Further information and advice is also available online at www.nhsdirect.nhs.uk.
