In daily life, people attach great importance to chest pain and headache caused by acute heart attack and cerebral infarction, because these two diseases can lead to sudden death and endanger life, but if leg pain can also be fatal, many people will not think so, the following is to introduce several kinds of leg pain that will kill people: acute lower limb artery embolism (thrombosis): often atrial fibrillation heart emboli, atherosclerotic plaque off or prolonged limb pressure leads to Arterial embolism thrombosis, the earliest manifestation is leg pain, rapid onset, rapid progress, usually 6-8 hours of severe ischemia can lead to limb muscle necrosis dissolution, causing acute renal failure, sequential cardiopulmonary failure life-threatening, so early diagnosis of early surgery to remove the embolism is very important, can save the limb to save life. The typical manifestations of the disease are the “5P” signs: (1) limb pain; (2) numbness; (3) paresthesia; (4) pallor; (5) loss of arterial pulsation in the foot. Lower extremity atherosclerosis-occlusive disease: The cause of this disease, along with coronary artery disease and cerebral infarction, is atherosclerosis leading to occlusion of different parts of the arteries, and patients have an equal or higher chance of acute heart attack, stroke, and death than patients with coronary artery disease. The early symptoms of these patients are usually cold legs and feet, numbness, leg cramps, and continue to develop is intermittent claudication limp that is: walking two or three hundred meters or even less than a hundred meters, leg pain, sit down to rest for a while the pain is relieved, continue to move leg pain again. Further development will appear continuous “resting pain”, sleeplessness, seriously affect life, continue to develop will appear lower limb necrosis, amputation, serious and even life-threatening. Lower limb deep vein thrombosis: first of all, the lower limb swelling and thickening, in addition to swelling, but also often accompanied by pain and discomfort, once the lower limb swelling and pain, the usual response is to press a press, rub a rub, which is a very dangerous action, easy to cause the lower limb deep vein thrombosis off, along with the blood flow back to the heart, and then from the heart to the pulmonary artery, causing acute pulmonary embolism, leading to sudden death.