Dozens of Scots have been hospitalised and wards shut down following a recent spike in winter diarrhoea and vomiting bug cases.
The latest figures from NHS Scotland show 24 people in Scotland required hospital treatment for confirmed or suspected norovirus infection in the past week.
The rise in admissions saw the closure of four treatment bays and a ward across three health boards – Lothian, Ayrshire and Arran and Borders.
Other cases are dealt with at home and go unreported.
Norovirus occurs all year round in the community, but peaks during winter.
There is no vaccine to protect against the illness since it continually changes and can be contracted more than once.
Symptoms usually clear up after two or three days.
However, vulnerable people such as babies, the elderly and those with existing health problems can be more seriously affected.
Health professionals are urging the public to take steps to cut their chances of catching or spreading the bug.
“Norovirus is a highly infectious stomach bug that causes outbreaks in the community, health and care settings,” Lisa Ritchie, infection control nurse consultant at Health Protection Scotland, said.
“It is therefore important that everyone plays their part in reducing the risk of outbreaks. If you are unfortunate enough to get norovirus, the best course of action is to stay at home until at least 48 hours have gone by without any symptoms.
“To help reduce the risk of outbreaks in hospitals and protect patients and residents, please do not visit hospitals and care homes if you are feeling unwell and until at least 48 hours have passed without any symptoms.
“You can’t build up immunity to norovirus, but there are some things you can do to protect yourself and others.
“The most important of these is washing your hands frequently and thoroughly with soap and water, particularly after using the toilet.”
There is no specific cure for norovirus, but sufferers are advised to drink plenty of liquid to replace lost fluids.
The rise in norovirus cases comes just weeks after health officials warned the lives of thousands of Scots could be at risk this winter due to a shortage of flu vaccinations.
Last month it was revealed that many private pharmacies had run out of the standard flu vaccine for people aged 65 to 74 and would not have fresh stock for several weeks. Many NHS GP surgeries were warning the vaccine intended for high-risk patients aged 16 to 64 would not be available until this month.