Quote Originally Posted by Gandalf_The_Grey
Actually the bacteria that's beneficial to your body has adjusted to it. Another example of natural selection I suppose, but they're quite at home in your body which is a tad saltier than the external world.
If you are trying to say that the normal flora in your mouth is immune to salt water rinses you're wrong. The salinity of most fluids in the body is only 0.9%. When you gargle with a salt water rinse it is much higher than that and normally not even normal flora can survive that just because they have been living in 0.9% salt content.