Varicose veins are not blood clots. In the physiological state, the blood from the veins is returning to the heart. Due to problems with the function of the deep veins and the function of the venous valves, the blood from the deep veins enters the superficial veins, and the direction of this blood flow is opposite to the normal physiological blood flow, and the blood accumulates in the veins in a large amount, which can lead to an increase in pressure in the veins and stagnation of the venous blood. This condition may lead to varicose veins thrombosis, because the change of blood from liquid to solid requires the participation of clotting factors and fibrin to complete. Thus varicose veins and thrombosis are two pathological processes, but because of the slow blood flow within varicose veins, the vein wall is a pathological state and there is a possibility of thrombosis within the varicose veins, which can cause localized redness, swelling, pain and other symptoms of superficial phlebitis in the patient.