Why is salt and water good for cuts and sores? And what is in it that helps and stings the affected area?

Question

Science homework =]

Answer 1

Salt is something that bacteria cannot multiply in, which is why salt is used as a preservative. Salt absorbs the available moisture that is essential for bacteria to multiply in.

Answer 2

The human body has a tightly controlled demand system for Na, potassium, copper and the like. This is true of animals, insects and bacteria as well. Salt absorbs moisture out of cellular fluid and cells cant' take this - the result is cell death.

It stings because without the protective barrier of the skin nerve endings and blood vessels are exposed to the salt. This is highly irritating as they need to be moist.

Salt water only works as a disinfectant while it is in use.. A better dressing is honey, with the bandage changed 3 times a day. If you check this out, you'll see that doctors are begginng to re-recognize the healing properties of honey.

Answer 3

Applying saline solution to a wound kills the bacteria in the area, which will reduce the risk of infection. Salt works by forcing water out of bacteria cells by decreasing the water potential around the cell. Now in this situation the system is entropically unfavourable, to balance out this the system wants the salt to diffuse into the cell, but because the cell membrane prevents this so the water is forced out.

Sorry I forgot to answer the second part: This I'm less familiar with, but pain is caused by nervous signals (or lack of in certain cases). Where there is a cut there will be severed nerves, which operate on electrical impulses. Salt solution is comprised of ions, which can act as an electrolyte which can confuse the signals.

Answer 4

salt dries up the area.  most bacteria like a moist environment.  also there are few that are salt tolerant that are medically significant.

Answer 5

germs and mostly harmful bacteria cannot survive in salt water, so in turn your healing process is speeded up because there are no harmful bacteria to hinder this. in olden days, they salted beef and pork and even fresh green vegetables to preserve them for long periods, way before the freezer was invented. i can't answer why it stings.