Musgrove Park Hospital in Taunton has visiting restrictions on four wards due to outbreaks of the Norovirus.
The hospital is asking for the public's help in keeping the winter vomiting bug under control.
Musgrove's medical director, Colin Close said: "Norovirus is a nasty infection, causing acute diarrhoea and vomiting. On top of that, it's highly contagious.
"There's an increased risk of infectious patients being admitted to the hospital at the moment and due to outbreaks of Norovirus four wards have restrictions in place.
"We can't eliminate the infection from our hospital without the public's help, but we're doing everything we can to reduce the risk of further outbreaks and we're keeping our website, www.tsft.nhs.uk and phone lines updated with the latest information for patients and visitors."
Please do not visit the hospital if you, or anyone you have been in contact with or has had any symptoms of diarrhoea or vomiting in the last two days and avoid visiting patients in the wards where there is an outbreak unless it is absolutely essential.
Local schools and nurseries have been affected by the virus. Children under 11 should not visit patients in the hospital unless absolutely necessary (except on the Children's and Maternity wards).
If you do visit the hospital, your hands must be washed with soap and water when you arrive at the ward and again when you leave. Alcohol gel alone is not effective against Norovirus.
