First, there is a risk of pulmonary embolism due to thrombus dislodgement, which may be life-threatening, even during the treatment period. Second, systemic anticoagulation and thrombolysis are the basic treatment for deep vein thrombosis, but there is a certain risk of bleeding, such as blood in the stool, hematuria, oral bleeding, nasal bleeding and even cerebral bleeding. If the patient has a history of bleeding, hypertension, stroke, etc., please make sure to tell the medical staff. Direct thrombolysis by intravenous catheter is an alternative treatment for deep vein thrombosis, which can effectively improve the rate of thrombus dissolution and reduce the incidence of thrombotic sequelae. Vena cava filters can reduce the incidence of pulmonary embolism and can effectively prevent fatal pulmonary embolism. V. Vena cava filters are artificial materials like artificial joints and artificial heart valves, which can be placed in the body for a long time. Possible complications include filter displacement, fracture, dislodgement, and damage to blood vessels. If a large thrombus is captured, it may lead to vena cava obstruction. Absolute bed rest, braking the affected limb and elevating it; avoid pressure, rubbing and hot compress. Seven, light diet, choose easy to digest, rich in vitamins, fiber and low-fat food, avoid greasy, quit smoking. Eight, if the patient has chest tightness, chest pain, cough, breathing difficulties, blue lips discomfort immediately inform the doctor. IX. Inform the doctor immediately if the patient has gum bleeding, nose bleeding, hematuria, bloody or black stool, bleeding spots on the skin, headache and vomiting, abnormal limb movement, etc. XI. During the treatment, symptoms may recur or even further aggravation of thrombosis may occur. XI. Other unpredictable complications may occur.