The three major causative factors of venous thrombosis are: blood flow stasis, venous wall damage and hypercoagulable state. People with high risk of DVT are: bedridden or inactive after surgery; trauma, obesity, hyperlipidemia or age over 40; patients with myocardial infarction, heart failure, stroke, nephrotic syndrome; patients with malignant tumor; patients with oral contraceptives, pregnancy, varicose veins or previous history of thrombosis, etc. Patients with surgery and trauma are especially prone to lower extremity DVT. Patients with acute major thoracic and abdominal surgery, hip or knee replacement surgery, hip fracture, severe trauma and acute spinal injury are at very high risk for thromboembolism. Lower limb swelling, pain and superficial varicose veins are the three main symptoms of DVT in lower limbs, pain is mostly cramping or dull pain, and superficial varicose veins are mostly the manifestation of the establishment of collateral circulation in the chronic stage. In some patients, the first and only clinical manifestation is sudden death, and the cause is “pulmonary embolism”: deep vein thrombosis can be detected in 70-90% of the patients with pulmonary embolism. Statistics: The mortality rate of pulmonary embolism is the third after cancer and coronary heart disease, so deep vein thrombosis is called the “silent killer”. The current treatment for lower extremity DVT includes anticoagulation, thrombolytic therapy, surgery and Chinese medicine. In addition, bed rest, elevation of the affected limb and local wet and hot compresses should be taken after the formation of lower limb DVT. The duration of bed rest is usually more than 14 days, and light activities can be carried out when the general symptoms and local pressure pain are relieved. When you get up and move around, you should wear gradient decompression stockings.