Drinking too much water is harmful to the body and can lead to water intoxication. Water intoxication can also be referred to as hypervolemic hyponatremia, which is characterized by: i. High volume, which means that the volume of water is too high, and too much water is drunk. Second, blood sodium is reduced, serum sodium concentration <130 mmol/L, plasma osmolality <280 mmol/L, the patient has water and sodium retention so that the amount of body fluid is significantly increased so it is called water intoxication. At this time, the amount of extracellular fluid increases, blood dilution, blood sodium further decreases, extracellular fluid is hypotonic, and water is transferred from extracellular to intracellular leading to intracellular edema. Therefore, the water retained in the intercellular fluid in the early stage is often not enough to produce sunken edema, but in the late stage or in severe cases, sunken edema may appear, which is one of the characteristics of water intoxication.