Low HDL level may not have any manifestation, some patients may have dizziness, and cerebral infarction and myocardial infarction may occur in severe cases. HDL has the function of lowering plasma cholesterol level. Low HDL level will reduce the transportation ability, which may lead to the increase of total cholesterol and LDL level, and will promote the progress of atherosclerosis. Patients with low HDL may not have any clinical manifestations, but only abnormal laboratory results. In some patients, atherosclerosis can lead to dizziness and chest tightness. Severe atherosclerosis can lead to cerebral infarction with impaired limb movement, and myocardial infarction can lead to chest pain and chest tightness. Patients with low HDL should pay attention to the monitoring of LDL and total cholesterol, and if necessary, should be given medication on the basis of dietary control, such as oral atorvastatin and other medications.