An outbreak of norovirus has led to the Royal Bolton Hospital temporarily banning visitors from eight wards.
The restrictions have been introduced in an attempt to contain the highly contagious vomiting and diarrhoea bug.
The wards affected are B1, B3, C2, C3, D1, D2, D3 and D4, a spokeswoman for Bolton NHS Foundation Trust said.
Anyone who has experienced sickness or diarrhoea in the past 48 hours is also asked to stay away from the hospital except in a genuine medical emergency.
Richard Catlin, the trust's assistant director of infection prevention and control, said: "Norovirus is something we take extremely seriously. It is something that has the potential to spread very rapidly.
"It is with regret that we have had to suspend visiting on a number of our wards due to norovirus. This is not a decision we take lightly but is always in the best interests of our patients.
"We are asking people to please bear with us and understand that the welfare of our patients is paramount."
The winter vomiting bug has also affected Southport and Formby District General Hospital where Ward 14A was temporarily closed over Christmas.
Andrew Chalmers, consultant nurse and deputy director of infection prevention and control, said: "Norovirus is short-lived but very unpleasant. You don't want it and our patients certainly don't.
"If you're affected, stay at home, drink plenty of fluids, wash your hands after using the toilet and prior to eating, and clean or disinfect contaminated surfaces."