Smoking is very harmful to blood vessels, the nicotine and nicotine in cigarettes can directly damage the walls of blood vessels and cause atherosclerosis, and smoking can cause spasm and contraction of blood vessels and insufficient local blood supply. When smoking for a longer period of time, it causes narrowing and occlusion of the blood vessels until it causes symptoms such as cold, numbness, pain or intermittent claudication of the lower limbs. This condition can cause limb ischemia and necrosis if not treated promptly. For smokers, the first rule of vascular lesion treatment is an absolute ban on smoking and they should stay away from second-hand smoke.