The effect of potassium chloride: (1) hypokalemia caused by the treatment of a variety of reasons, such as eating, vomiting, severe diarrhea, application of potassium diuretic, hypokalemic familial periodic paralysis, caused by long-term use of glucocorticoid and hypertonic glucose supplement after hypokalemia. (2) the prevention of low potassium when the patients have blood, loss of potassium, especially if hypokalemia patient harm is large (such as the use of digitalis, preventive patients) need added salt, such as eating less, severe or chronic diarrhea, long-term use of adrenal cortical hormone, potassium losing nephropathy, Bartter syndrome. (3) digitalis poisoning caused by frequent, multiple contraction or arrhythmia.