Symptoms of blood clots in the legs are mainly the appearance of obvious swelling and also pain. Symptoms vary according to the type of blood clots and are mainly categorized into arterial thrombosis symptoms and venous thrombosis symptoms. 1. Arterial thrombosis: in case of acute arterial embolism, the manifestation is the sudden onset of pallor, coldness, numbness, pain, pulselessness, abnormal sensation of the lower limbs, etc., and in severe cases, necrosis or gangrene of the limbs will occur within 24 hours. If it is chronic arterial thrombosis, often in the arteriosclerosis occlusion on the basis of thrombosis, patients will have intermittent claudication in the early stage, that is, after patients walk a distance, there is soreness and pain in the calf, which can be relieved after resting, and clinically it is often based on the distance of claudication to determine the severity of the disease, and in the late stage, there will be resting pain, and then there will be necrosis and gangrene of the limb. 2. Venous thrombosis: venous thrombosis is often deep vein thrombosis, which is manifested by swelling and pain in the limb, accompanied by changes in the color of the skin of the limb, as well as the increase in the local skin temperature, and the expansion of the superficial subcutaneous veins will also be seen, and it is recommended that the patient should rest in bed and avoid activities for deep vein thrombosis, in order to prevent the dislodgement of the thrombus and the occurrence of pulmonary embolism. Patients should go to the hospital for examination as soon as the symptoms of blood clots in the legs appear, so as not to delay the condition, and receive treatment under the guidance of the doctor.