Swelling in the legs of the elderly is mainly due to the following reasons: 1) venous thrombosis or venous valve insufficiency in both lower limbs: it leads to the obstruction of venous return and the increase of pressure in the veins, which makes plasma extravasate into the tissue interstitial space, and thus causes edema; 2) total heart failure or right heart failure: due to the diminished pumping function of the heart or the increase of pressure of the right heart due to certain causes, it influences the venous return of the inferior vena cava, and the blood is stagnated in the lower limbs. Edema mostly starts from the foot and gradually spreads to the calf, which is depressed edema; 3, nephrotic syndrome or nephritis: it causes swelling of legs, but it is mostly accompanied by edema of eyelids, face and other parts of the body; 4, cirrhosis of the liver or malnutrition: it can lead to hypo-proteinemia, which can also cause edema, which is mostly peripheral edema, and in addition to swelling of the calves, it can also be accompanied by ascites, pleural fluid and other symptoms.