Gloucestershire Royal Hopsital has closed its wards to visitors following an outbreak of a diarrhoea and vomiting illness.
Several wards at the hospital have been affected by the illness, of which there are a number of cases in the community at this time of year.
Director of nursing Maggie Arnold said: "This is a precautionary measure and good infection control practice to protect patients and to control the spread of the illness.
"I hope that families and friends will understand that we need to protect our vulnerable patients and that is why we are asking them not to visit for this short period.
"We hope to be in a position to reintroduce visiting at GRH in a matter of days.
"We would strongly urge people to take notice and act on the Combat Norovirus campaign messages which have got a high profile presence on posters, large banners and signs at both main hospitals."
The D&V illness is usually over within 48 hours, but is highly infectious, which is why the Trust needs to limit the number of people moving in and out of wards.
Visiting to maternity wards is not affected. Visiting to children's wards is restricted to parents and carers.
Exceptions can be made for relatives hoping to visit on compassionate grounds. These visitors are being asked to speak to a member of ward staff on entering the ward.
While visiting restrictions will be lifted as soon as possible, visiting will be suspended at least until Friday when it is next due to be reviewed.
Further updates will be issued before the weekend.
