Dehydration of the body is especially spread in the summer. Dehydration is insufficient water in the body. This is a violation of the water balance in tissues, organs and throughout the body as a whole. Especially it is dangerous for children and people of advanced age. This condition can occur with diarrhea, increased sweating, sun or heat stroke, burn. Among the main symptoms are allocated — drowsiness, thirst, lack of appetite, rapid pulse. The human body consists of more than 60% water. Therefore, it is necessary to monitor the water balance. Doctors advise to drink 1,5-2 liters of water a day. It is useful to drink a glass of water on an empty stomach in the morning, but at night you do not want to drink water. Water cleanses the body, moistens tissues, transfers oxygen to organs and cells, improves metabolism. If a person drinks inadequate amounts of water, a certain consequence arises. Among them: a decrease in immunity, rapid aging, lethargic skin and much more. Water should be drunk often, but in small quantities. Drinking enough water reduces back pain, migraine, lowers cholesterol and blood pressure, prevents kidney stones, improves brain activity. But it is worth remembering that excessive use of water can do harm, not good.