Water is an absolutely essential nutrient of the body. One can survive for months together without other nutrients, but not without water. But many people are ignorant about the importance of water.60 per cent of an adult’s body weight is constituted by water and the percentage is higher for a child. Water is a fluid in which all essential body processes occur. It may be within or outside cells. All nutrients are carried across the body in water. Waste products are removed from the body via water. It helps to form structure of large molecules essential for various processes in the body. It actively participates in many chemical reactions. It also serves as a solvent for minerals, vitamins, glucose, among others substances essential for the body. Water serves as a lubricant for the various joints of the body. It is due to gradual depletion of this lubrication that people start suffering from stiffness and pain of joints with advancing age. It also serves as a shock absorber inside the eyes and spinal cord. During pregnancy it protects the fetus in the amniotic sac (gestational sac where baby is held in mother’s womb). Water helps in the regulation of the body temperature and also in maintaining the volume of blood in the body. It helps to clear the bowels and aids in digestion. Thus importance of water can never be underestimated. When the body needs water, a person feels thirsty. Many people satiate this thirst by drinking tea, coffee, alcohol or other beverages. But that serves the purpose only partially. That is why one feels the need for drinking water even after drinking juice or soft drinks. How much water a person drinks depends on, climate, nature of work, other medical conditions like diabetes (one has intense thirst in diabetes), conditioning of body and availability of potable drinking water, are some of the factors which influence one’s drinking habits. Therefore, a general requirement is difficult to establish. Water is lost from the body as urine, sweat and other invisible losses. If more water is lost than the intake, one develops dehydration. Mild dehydration manifests as dryness of mouth, but severe dehydration can lead to shock and kidney failure which can be fatal.Therefore, it is important for people to take adequate amounts of water. On average, it is recommended that eight to 10 glasses of water is sufficient for an adult doing ordinary physical work. Drinks of various kinds supply some water to the body. Fresh vegetables and fruits are yet another source of water. Many other foods like meat and cheese contain 50 per cent of water. But water by itself is the prime and most healthy source of water. Beverages like tea and coffee, alcohol, cause gastritis if taken in large amounts. They also have a diuretic action, that is to say, they promote loss of water from the body. Meat and cheese increase cholesterol and obesity. Therefore, it is good to take other substances in moderation but they should not be substituted for water.People should understand the importance of water and start drinking sufficient amounts of water. Dr Rachna Pande is a specialist in internal medicine at Ruhengeri Hospital