The normal range of blood potassium is 3.5 to 5.5 mmol/L. Blood potassium less than 3.5 mmol/L is called hypokalemia, and higher than 5.5 mmol/L is called hyperkalemia. Blood potassium plays an important role in maintaining muscle excitability. Hyperkalemia can cause weakness in the limbs, fatigue, and even respiratory muscle weakness leading to asphyxia. Hyperkalemia can cause cardiac arrhythmia, which can be severe enough to lead to cardiac arrest. Potassium in the body mainly comes from food, and the content is mainly affected by the discharge and intake of potassium. Kidney is the main organ to discharge potassium, and when there is renal failure, the obstacle of potassium discharge can lead to hyperkalemia, and exogenous potassium absorption and intake of too little, diarrhea, gastritis and large loss of potassium ions can lead to hypokalemia. The regulation mechanism of potassium in human body is very complicated and affected by many factors. If some of the above clinical manifestations occur, it is necessary to go to the hospital in time for examination, identification of the cause of the disease, and active treatment, so as to avoid delaying the time of treatment.