Science Questions

Why is it recommended to put salt on cuts? It seems to be popular advice with dealing with cuts on the inside of your mouth, for example, but what’s really happening and is using salt actually a good idea? Veronica

A lot of bacteria, especially the ones that cause ones in the mouth are bacteria like streptococci, and some of the other mouth-dwelling organisms and they’re quite salt-sensitive. When you put a big dose of salt on them the salt is a bit like putting salt on a slug. It pulls the water out of the bacteria and dehydrates them and can damage them. Other bacteria though like staphylococcus (aureus) actually like salt so if you have a wound on your finger it might not actually be so good for that because it will kill the bugs in there which are not staphs but it might end up with your being colonized entirely by staphs. It’s quite good in very high concentrations it stops bugs growing. The likelihood of you getting enough concentration of salt on the wounded area to kill the bugs is quite unlikely. It does have a soothing effect though.

November 2007