ORS is an Oral Rehydration Solution, a glucose-based salt solution composed of sodium chloride, glucose, anhydrous, potassium chloride, trisodium hydrate, and citrate dissolved in one litre of water. It helps to bring down the fluid lost during diarrhea.  
In the diarrhea state, there is an imbalance, and significantly more water is produced than reabsorbed water resulting in the loss of more water than usual. Along with the loss of water, sodium and potassium are as well lost. Water is absorbed by sodium via osmosis when the concentration of sodium in the intestine wall is adequate. If there is an inadequate concentration of sodium, the body does not absorb water.
The saline bottle (contains sodium chloride and water) directly transfers both water and sodium into the bloodstream, but saline water is taken through the mouth. So, the intestinal wall is not able to absorb neither water nor sodium. If glucose is added to the salt solution, the body is able to absorb the glucose, salt and water (as found by Dr Dilip Mahalanabis).
Still, the intestine wall can absorb glucose molecule during diarrhea. So, the ORS solution utilizes the glucose to enable the sodium to be carried out via a co-transport coupling mechanism.
Benefits of ORS:
  • A productive treatment for \(90 - 95%\) of patients who are affected by diarrhea no matter the cause.
  • Does not have risk of injection.
  • Can be self-administered.
  • Shows the result within minutes of administering.
  • Can be administered very fast (\(500\) \(mL\) in less than one minute).
  • Safe for all age groups, even infants.