An outbreak of the Norovirus has forced medics to close hospital wards in Cornwall this morning.
People are being urged to avoid the Royal Cornwall Hospital after three wards have been contaminated with the vomiting bug.
Senior staff at the hospital have issued a "Black Alert", known as an "OPEL 4" which the NHS classifies as a "serious incident".
Norovirus is one of the most common stomach bugs in the UK. You are likely to have caught Norovirus if you experience a sudden sick feeling, projectile vomiting and watery diarrhoea.
Other symptoms can include a slight fever, headaches, painful cramps and aching limbs. Symptoms generally only last for about two to three days.
If you think you have contracted it contact NHS direct but stay at home, as you could put others at risk by being in hospital.
Symptoms do not last long, however, you're actually contagious for up to three days after you've recovered - and some people may even be contagious for two weeks.
Johanna Floyd, general manager for urgent emergency care at the Royal Cornwall Hospital, tweeted: “Royal Cornwall Hospital Opel 4, three wards closed with Norovirus. Staff are working extremely hard. The hospital is under significant pressure this morning", adding: "Take advice from your GP to manage any Norovirus symptoms at home.”