Sodium chloride or more commonly, "salt" is essential for survival. A normal daily intake is about 1/2 oz. Trouble starts when you get rid of it faster than you eat it. The body loses salt in sweat and urine . Warm climates and physical exertion will increase the loss.

 

First symptoms of salt deficiency are muscle cramps, dizziness, nausea and tiredness.  The remedy is to take a pinch of salt in half a liter (pint) of water. If you have salt tablets , break them up and dissolve in appropriate amount of water.

 

If you run out of salt you can use sea water but it must be diluted with plenty of freshwater. A pint of seawater contains about 3/4oz of salt.

Some plants contain salt.  In North America the best source is the roots of the hickory trees, in South east Asia those of the Nipa palm can be used. Boil the roots until all the water is evaporated and black salt crystals remain.

 

If no direct sources of salt are available you will have to rely on getting it through animal blood, which should never be wasted as it is a valuable source of minerals.