Hospital beds have been closed and non-emergency surgery halted after a viral outbreak at Frimley Park Hospital near the Surrey/Hampshire border. A spokesman said control measures were brought in on Tuesday after the infection was confirmed among several members of staff and patients.
Vomiting and diarrhoea have been caused by the Norovirus, a winter vomiting bug, and clostridium difficile.
The closure of 80 beds to new admissions will be reviewed next week.
As many non-emergency surgery cases as possible are being diverted to neighbouring hospitals.
Children banned
Only wards F7 and F8 have been affected by the viruses but visiting restrictions are in place throughout the hospital, which is based at Frimley, near Camberley.
Dr Nigel Cumberland said: "It is imperative that anyone who has experienced vomiting or diarrhoea within 48 hours does not visit the hospital.
"These viruses are usually imported into the hospital from the community and the last thing we want is for further infection to be brought in while we are trying to deal with this outbreak."
Mr Cumberland said it was particularly important that children should not be brought to the hospital.