All cells in the human body require water to function, and you may not realize that the water content of the human body is very high, with adults containing about 65-70% of their body weight in water. Therefore, if you don’t consume enough fluids, or if you lose fluids because of vomiting or diarrhea, you may experience symptoms of dehydration. In this case, the fluids and minerals that keep the body functioning are in a serious imbalance. The basic amount of fluid needed in a day can usually be calculated at 30-40 ml/kg per day to ensure that all body cells get the water they need. In the case of vomiting or diarrhea, you may need more water to maintain a daily urine output of 1,000 to 2,000 ml and to adjust your water intake according to your urine output. However, special care should be taken in patients with heart, lung, kidney and other organ dysfunction to prevent too much fluid from aggravating the burden on these organs. Remember that all fluids (soup, milk, and even ice cream) should be counted in your target daily fluid intake.