During ward visits, patients or family members often ask me a question: Why does the hemiplegic limb swell, and how to avoid and reduce the swelling? The following is a brief analysis of the causes and some suggested treatment methods. There are two common causes of swelling in hemiplegic limbs, one is venous reflux obstruction. The venous return of human body mainly depends on the pressure difference between veins and heart, and the squeezing pressure of muscle contraction on the vessel wall. The role of this squeezing pressure is particularly important because of the thinness and poor elasticity of the vein wall. But when the limb is paralyzed, the muscle stops the contraction activity because of the loss of innervation, and the squeezing pressure of the muscle on the venous vessels also disappears, which leads to the obstruction of venous reflux. Secondly, the nutrient metabolism is impaired. After limb hemiplegia, the loss of innervation, the hemiplegic side of the limb will be secondary to nutrient metabolism disorders, so that the diastolic function of blood vessels is dysregulated, contraction and diastolic response becomes sluggish, venous blood return velocity slows down, blood stays in the veins, so that the pressure in the lumen of the veins increases, and fluid is squeezed outside the walls of the vessels and stays in the tissue interstices, and swelling is produced. For mild limb swelling, elevate the affected limb and enhance active and passive activities to allow venous blood to flow back as soon as possible, the edema will disappear quickly and will not cause greater harm. However, if the edema lasts for a long time, the protein components will be deposited and become fibrous tissue, and joint stiffness and contracture may occur.