Hyponatremia is often referred to as hyponatremia, and it is important to find the cause of hyponatremia and then choose the appropriate treatment plan. Generally, when hyponatremia occurs in the elderly, it is often caused by poor diet and insufficient sodium chloride intake in the usual diet, which can be recovered quickly by giving a high-salt diet or even intravenous supplementation of concentrated sodium homemade salt capsules taken orally. If the hyponatremia is caused by long-term oral diuretics, the diuretics can be temporarily discontinued, and active sodium supplementation will be corrected quickly. If the fluid retention is high, that is, the water content in the body is high, you can consider temporary oral tolvaptan, a diuretic, which has a much greater effect on water than sodium and can also correct hyponatremia quickly. It is necessary to be alert to the fact that some patients with tumors may have paracrine function, resulting in severe and persistent hyponatremia, which cannot be corrected even by intravenous sodium supplementation or oral salt capsules, and all of them need to improve the relevant oncological examination.