|MadSci Network: Medicine|
Gargling with salt water helps to kill bacteria and prevent infection. The salt water sets up a hypertonic environment; water rushes out of the bacterium by osmosis, killing the bacterium. So it is not a question of pressure exerted on red blood cell walls, but rather the pressure exerted on the bacterial cell wall. What else is salt water good for? Sterile saline (salt water) is used widely in medicine to flush wounds, and a dilute solution is used to treat contact lenses by matching the ionic strength of the fluids of the eye. Putting pure water in the eye along with a contact lens can be very uncomfortable!
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