The common causes of low potassium include the following: First, the cause of drugs, mainly seen in patients with heart failure who apply diuretics in large quantities, and are prone to low potassium after excessive diuresis. Second, insufficient intake of potassium containing food, such as right heart failure patients, due to the gastrointestinal tract bruising resulting in gastrointestinal mucosal edema caused by loss of appetite, especially the intake of fresh fruits and green leafy vegetables, or combined with digestive system diseases resulting in malabsorption, may appear low blood potassium. Third, excessive loss of potassium, such as nausea, vomiting and severe diarrhea due to digestive system diseases, resulting in a large amount of digestive fluid loss from the gastrointestinal tract, which can easily lead to hypokalemia if the patient does not eat enough at the same time.