Fascinated by how much better I felt after having an intravenous saline drip, I sought to find out why this worked. Both medical and lay people said it was because I was dehydrated.

Having the solution administered intravenously meant it reached my blood stream directly. This also meant it was much faster.

Had I taken the solution orally I would have needed to digest it before it was available to my blood. Normal saline solution is salt (sodium chloride) in sterile water.

The amount of salt in solution is important 0.9 percent is the norm because this is close to the concentration of blood.

Having the concentrations the same allows water and blood to move freely in and out of the blood cells of the body.

In allowing water to move freely in, my blood cells became hydrated. The principle is a basic law of physics.

Of course water would also freely move into my blood cells if the saline solution were less concentrated than 0.9 percent.

The danger here is that because the concentration of salt in the blood is greater, water would move into the blood cells and not come out. This would result in cells bursting.

Similarly saline solutions with salt concentrations higher than 0.9 percent can result in blood cells shrivelling up and dying.

The addition to the solution, in my case, of a mild pain reliever and Gravol for stomach upset helped alleviate these symptoms that contributed to my feeling better.