Three wards at the Wrexham Maelor were closed over the weekend due to an outbreak of Norovirus.
On Friday Betsi Cadwaladr University Health Board said that 11 people had shown symptoms of the sickness and diarrhoea bug. This resulted on admission to the three wards being suspended.
However visiting hours for the rest of the hospital remained the same.
Additional infection controls were also enforced to prevent the virus from spreading. Visitors are being told to look out for notices around the hospital, and reminded to wash their hands while entering and leaving a ward.
Visitors are urged not to bring babies or children with them to the hospital.
Anyone who had suffered sickness or diarrhoea over the last 48 hours was advised not to visit the hospital. Those who have experienced these symptoms and have a routine appointment are advised to phone the hospital for guidance on what to do beforehand.