Three wards at South Tyneside District Hospital have been closed as bosses battle to control an outbreak of Norovirus.
Visitors have been asked to stay away from the site in a bid to stop the spread of the winter vomiting bug.
The outbreak of the illness comes just over a year after an elderly care ward at the hospital was closed for the same reason.
South Tyneside NHS Foundation Trust’s medical director, Dr Shaz Wahid, said: “We are currently dealing with an outbreak of Norovirus, which is a very infectious vomiting and diarrhoea bug.
“While Norovirus is the most common stomach bug in the UK and is, generally, mild, our first priority must be to protect vulnerable patients and, consequently, we are asking people to respect our current visiting guidance.
“Our infection prevention and control team are working extremely hard to prevent transmission of the illness, including constantly monitoring all ward areas to ensure that appropriate measures are in place so that affected areas can be re-opened as quickly as possible.
We are currently dealing with an outbreak of Norovirus, which is a very infectious vomiting and diarrhoea bugDr Shaz Wahid
“The public have a very important role to play in helping us to protect patients and we really appreciate their support.
“We know how important visiting is to patients, and their relatives, friends and carers, and we are checking the situation hourly and hope that normal visiting access can be restored very soon.”
It is not currently known how many patients have contracted Norovirus.
Visitors who have been unwell with symptoms of diarrhoea and vomiting have been asked to stay away from the hospital until they have been symptom-free for 48 hours.
Once symptom-free, they should also check with the ward before arriving.
The NHS in South Tyneside, and the rest of the North East, is currently under severe pressure.
It comes after the recent extreme weather in the region led to soaring attendances at accident and emergency departments.
People have been asked to stay away from A&E unless they are seriously unwell or in need of critical or life-saving care.
Those who suspect they may have Norovirus are advised to stay at home and drink plenty of fluids, and ask for a consultation with their GP should the symptoms persist.
They should also stay away from work or school until they have fully recovered and been free of symptoms for 48 hours.