Medical elastic stockings have the function of promoting venous blood flow back to the heart and are designed according to the different physiological pressure gradients from the bottom to the top of the lower extremities, establishing the highest support pressure at the ankle and gradually decreasing the pressure up the leg to 70%-90% of the maximum pressure value at the gastrocnemius (calf belly) and 25%-45% of the maximum pressure value at the thigh. This decreasing change of pressure can promote the venous blood flow back to the lower limbs, effectively relieving or improving the pressure on the veins and venous valves of the lower limbs, so that the clinical symptoms of venous insufficiency can be significantly improved and the leg discomfort caused by varicose veins, mild ankle swelling, leg fatigue, pregnancy edema and other related problems can be relieved. How to choose medical compression stockings? According to the different pressure gradients, there are four types as follows: 1. First level pressure gradient (15-21) mmHg (health care type): capillary dilation, reticular varicose veins, stage C1 varicose veins with heavy lower limbs; 2. Second level pressure gradient (23-32) mmHg: varicose veins C2 stage C4, deep vein insufficiency, after vein stripping surgery, after endovenous laser coagulation, varicose veins in pregnancy with lower limb swelling; 3.Tertiary pressure gradient (34-46) mmHg: varicose veins stage C4-C6, post-deep vein thrombosis syndrome, traumatic edema, congenital venous malformation of the lower extremity; 4. Four-level pressure gradient >48mmHg: patients with fixed edema, irreversible lymphedema. Wearing time of medical elastic stockings It is generally recommended to put them on when you get up and walk, and you can take them off when you rest at night. If you do not feel too tight, overheated or allergic when wearing them, it is recommended to wear them for a long time, and patients with venous ulcers are recommended to wear them for life. Those who can not use medical elastic stockings: 1, lower extremity atherosclerosis occlusive disease with intermittent claudication of the lower extremity; 2, acute dermatitis, exudation or eczema, skin rupture with purulent infection; 3, deep vein thrombosis in the acute phase; 4, lower extremity arterial bypass grafting; 5, loss of compensation of congestive heart failure and other patients with caution.