Varicose veins can cause thrombosis because the blood flow in varicose veins is very slow, the blood is stagnant, fibrin exudes to form solids, and the aggregation of white blood cells, red blood cells, and platelets can lead to thrombosis, which can fill the entire lumen of varicose veins, and the patient will show redness and swelling of the skin, tenderness, the ability to palpate hard streaks, and high skin temperature. This is an aseptic inflammatory disease, which is treated by activating the blood circulation and removing blood stasis, with topical Xanax, oral Veritin, Diosmin, and anticoagulation. Because the superficial vein thrombosis may enter the deep vein, which can lead to deep vein thrombosis. If the deep vein thrombus is dislodged, it will enter the pulmonary artery with the blood and form a pulmonary embolism, which will endanger the patient’s life, so anticoagulation is also very important. If these treatments do not completely improve and the patient’s symptoms are severe, surgery can be performed to remove the vessel with the varicose vein thrombosis.