If you drink too much water a day, for normal people it will lead to an increase in the number of urine, but it will not have too many serious effects. If the patient has kidney disease or heart disease, there will be a series of effects. For patients with kidney disease, if they drink too much water a day, often due to the decrease in glomerular filtration function there is no way to completely excrete the water drunk, which will lead to an increase in blood volume in the body, which in turn will lead to edema. In mild cases, it may lead to puffy eyelids and edema of both lower limbs, and in severe cases, it may lead to generalized edema and even abdominal and pleural effusion and pericardial effusion. For patients with heart disease, the increase in blood volume after drinking too much water may induce heart failure, resulting in panic, chest tightness, and difficulty breathing.