The reason for the swelling of legs and feet in the elderly may be due to the insufficiency of important organs of the elderly, such as the heart, liver and kidneys, as follows: 1. When the left heart fails, the ejection fraction decreases, so the return of venous blood to the heart decreases, and these tissue fluids increase, and the legs and feet are in the lowest position in the body, and swelling occurs first; 2. When the liver fails, there is If the liver fails, the patient’s ability to synthesize protein decreases, leading to hypoproteinemia, and the colloid osmotic pressure in the human blood vessels decreases, and the blood penetrates into the tissue fluid, so the legs and feet become swollen; 3. Kidney insufficiency, such as water and sodium retention, can cause hypoproteinemia because more protein is excreted, which also leads to swelling of the legs and feet. In addition, there is also deep vein thrombosis in the lower extremities of the elderly, which affects the venous blood return and usually occurs in one of the limbs, resulting in swelling of the legs and feet.