Wards at two Highland hospitals have been closed after a break-out of diarrhoea and vomiting.
NHS Highland says it cannot confirm the infection is norovirus, or the winter vomiting bug, but says it is "likely".
The Rosebank ward at Caithness General Hospital and ward 2A at Raigmore Hospital in Inverness has been closed to new admissions.
A total of 17 staff and 15 patients at the two hospitals have been affected by the outbreak.
Dr Emma Watson, NHS Highland lead infection control doctor, said: "There is no specific treatment for a norovirus infection and it is not usually necessary to visit a doctor.
"The best course of action is to stay at home, take paracetamol to relieve symptoms of any fever and to drink plenty of water to prevent dehydration."
Norovirus, which causes diarrhoea, nausea and vomiting, spreads in the air and is very difficult to contain.
Anyone booked into the hospital for an appointment, who has suffered any of the symptoms, is asked to contact their doctor before arriving.
For more information on Norovirus, visit the STV Health Centre, brought to you by NHS inform.
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