Restrictions have been placed on four additional wards at Hairmyres Hospital in East Kilbride, South Lanarkshire, with no new patients being admitted to certain areas of them.
NHS Lanarkshire said that 63 patients and 28 staff have experienced symptoms of the bug since the outbreak began about a week ago.
Eight patients and three staff remain symptomatic.
The health board said that strict standard infection control precautions are in place under the guidance of infection control specialists.
The situation is being monitored and the hospital remains open to emergency admissions as normal.
Susan Friel, chief of nursing services at Hairmyres, said: "Our priority is always to ensure the safety of our patients."