Since the first man stood on earth, when the nature is still kind until today, every living creatures still need water, no doubt about that. but does anybody know that drinking water is not only about relieve our thirst ? that water is the second most essential need of our body (after air) is actually a natural cure ?. From the view of Natural Medicine to the latest modern science, there are basically no differences about what this liquid object can do.
Naturally, human body is loaded with liquid equal to 60-70 cc (according to sex) times our weight (in kilogram), for example you are a man, 80 kg. So your body liquid is around 70 cc x 80 = 5600 cc ~ 5.6 liter of liquid. The Nature of water is dissolving almost everything, except oil, fat and its products. That dissolving property of water is one of reason why we need water, another reason is water acting as a cooler when our body temperature above its natural state, water is a transport media for our body chemicals and the equilibrium maintainer.
Now, from the point of view of natural medicine, lets us discus about water as a natural elixir. Do you know vitamins Right ? there are many type of them, from A-Z, 1-12 
. There are at least 2 vitamins that are water soluble; C and B (there are 12 vitamins that within the B vitamins group, from 1-12). Human body cannot produce vitamin so we get it from food then as its nature, water will transport it to our vital and if there are too much vitamin in our body, water will act as dump truck to transport the vitamins to kidney for excretion.
Another amazingly natural properties of water are body cooler and equilibrium maintainer. When our body temperature raising, naturally because our activities such as sport, or because of pathogenic activities like infections, one thing that we must do is drinking as much as water as possible, because with much water within our body, the body temperature will decrease as a water that extinguish fire, and when the brain thinks that our body is contain too much water, than naturally, the excessive water will be thrown away through urine and sweat, so you don’t need to worry about drinking too much water right ?. the last but absolutely not the least, is water natural ability to maintain the balance of electrolytes in our body, for example there are lack of natrium (sodium) within our cell, then the natrium outside the cell will moving into the cell through it membrane (called semipermeable membrane) with the help of water (of course).
That only few of water’s natural abilities, but the fact is water is still so important although we don’t know its nature completely. So we still gonna drinking when thirst struc ? I hope not . remember, always drink minimum 8 glasses of fresh water daily, try to drink it in separated portions (even you can drink 8 glasses in row) so you can get the most beneficial results.