Hypokalemia refers to the serum potassium concentration less than 3.5mmol/L. The causes of the disease mainly include insufficient potassium intake such as gastrointestinal obstruction, excessive potassium excretion such as renal tubular acidosis, and transfer of potassium to the tissues such as metabolic alkalosis. 1. Insufficient potassium intake: mainly due to gastrointestinal obstruction, coma, prolonged fasting, anorexia nervosa, etc., resulting in insufficient potassium intake, but also due to prolonged infusion of liquids that do not contain potassium salts or insufficient potassium content in parenteral nutrition solution. 2. Excessive potassium excretion: a large amount of potassium can be lost from the digestive tract, such as severe vomiting, diarrhea, enterocutaneous fistula, etc. Excessive potassium can also be excreted from the kidneys, which is commonly seen in long-term application of furosemide or thiazide diuretics, polyuria stage of acute renal failure, renal tubular acidosis, etc. 3. Potassium transfer to tissues: mainly seen in large amount of insulin or glucose infusion, also seen in metabolic and respiratory alkalosis. When hyperkalemia occurs, timely examination is needed to clarify the cause and standardize the treatment according to doctor’s prescription to avoid delaying the condition.