Drinking water at night will edema, usually due to four reasons. First, nephritis, nephrotic syndrome, usually the kidneys have excretory functions, such as drinking too much water in the evening, will be through the role of water diuretic, and accelerate the excretion of urine does not lead to edema, such as after drinking water will lead to edema, usually glomerular filtration rate is insufficient or renal tubular reabsorption disorders, so renal insufficiency will lead to edema after drinking water at night. Second, common diseases are hypothyroidism, when the body thyroid function is dysfunctional, it will lead to a decrease in the basal metabolic rate, so it will lead to the occurrence of mucus edema around the body. Third, there are common reasons for edema after drinking water at night and heart failure, when a person has heart failure, the effective circulating blood volume is insufficient, blood metabolism and water secretion capacity is diminished, so it can also lead to edema after drinking water. The least common cause is certain cirrhosis of the liver, especially people with a long history of hepatitis, be alert to edema caused by cirrhosis, but this edema is to abdominal edema called ascites as a significant clinical manifestation.