Staff at Hull Royal Infirmary are tackling this winter's first outbreak of Norovirus.
Hull and East Yorkshire NHS Trust is asking visitors to stay away from the hospital if they are carrying respiratory infections and diarrhoea as ward 70 remains closed with the vomiting bug.
The Hull and East Yorkshire NHS Trust has said visitors should not go to the hospital for at least 48 hours after symptoms of diarrhoea and sickness have stopped, and only when they are feeling well enough after a respiratory infection.
Hospitals are particularly vulnerable to Norovirus, which spreads quickly in closed environments and among people with weakened immune systems.
Greta Johnson, lead infection prevention and control nurse at the Trust, said:
''The Trust is also appealing to people who do come to hospital to wash their hands as soon as they come onto wards, using the hand-washing facilities at the entrance as soon as they walk through the door.
Good hand hygiene, such as washing hands after using the toilet, is essential to prevent Norovirus and other infections spreading.
Covering your mouth when you cough or sneeze and disposing of paper tissues properly can also prevent the spread of respiratory infections passing through the air.
Wards and bays can only reopen when they have had no new reported cases and patients have been symptom-free for 48 hours.