Water is widely distributed in nature compound. The average water content in the adult human body is about 60%. This means that the average, 72 kilogram man is made up of about 45 liters of water. In women, the higher amount of body fat, percentage of water is a bit smaller. The body of a newborn baby contains 75%, and the human embryo almost 98% water. Each body contains water and as such striated muscles consist of 75% water, 70% of the skin, connective tissue 60%, fat 20%, bone 25%, renal 80%, 70% of lung, liver 68%. Water is a substrate for many processes (eg digestion) or product (eg, breathing oxygen). Water is involved in the transport of substances in the body. The water in the body occurs in three areas: the intracellular space, in the extracellular space and in the intercellular space. These spaces vary in anatomical location, physiological functions and chemical composition. The fluid in the extracellular space are: blood plasma, tissue fluid and lymph. Fluid in the intercellular space includes: cerebrospinal fluid, the fluid in the chambers of the eye, the fluid in the body cavities (eg, peritoneum), fluid in the joint capsules and digestive juices found in the gastrointestinal tract (saliva, gastric juice, pancreatic juice, bile and intestinal juice). Water contained in our bodies is subject to constant exchange. A healthy body maintains a very strict control over the balance of fluids, in which even a 1-2% loss of water may adversely affect the functioning of the whole system. Without food we can survive several weeks, but no water - only a few days. Water has many benefits. Drinking plenty of water helps prevent constipation. In our society where many people are overweight, the fact that water is the drink totally deprived of calories (energy) is very important. Drinking water contain many different minerals. Their level in tap water varies from region to region of origin. Bottled water differs radically from it in terms of its content in minerals.