Gargling salt water has been found to reduce the symptoms of coughs and colds and to stop them getting worse, researchers say.
And now they want to find out if it could help people with mild symptoms of the coronavirus, which infects the airways in a similar manner.
University of Edinburgh experts are recruiting people to take part in a study to test whether gargling with salt water could boost the body's antiviral abilities.
The idea for the study came from ongoing research into upper respiratory infections — which commonly cause coughs and colds.
People with those illnesses were found to benefit from gargling regularly with salt water in a trial dubbed ELVIS (Edinburgh and Lothians Viral Intervention Study).
Results from the ELVIS trial, published last year, found people who gargled saline had less severe coughs, less congestion and colds that lasted two days less, on average.
They were also less likely to pass on the cold to family members, or to resort to taking medicines from a pharmacy, compared to people who did not gargle.
They suggested direct contact with salt has a toxic effect on the viruses themselves, or stimulates 'innate immune mechanisms' inside cells in the airways.
Salt may also be used by the body's cells to create a chemical called hypochlorous acid, which is found in bleach and known to kill viruses, the researchers said.