Whether LDL 5mmol/L is serious or not should be evaluated for cardiovascular and cerebrovascular disease risk, and patients with high risk have more serious conditions. The normal value of LDL is 0~3.37mmol/L, 5mmol/L obviously exceeds the normal value, but for patients with simple LDL elevation, not combined with other risk factors, belonging to the low-risk patients, the severity of the condition is relatively low, and the lipids can be controlled by diet. For patients who already have cardiovascular and cerebrovascular diseases, or patients who combine multiple risk factors, such as family history of early-onset cardiovascular and cerebrovascular diseases, carotid plaque, hypertension, diabetes mellitus, etc., such patients belong to the high-risk patients, and the risk of the condition will be significantly increased, and they need to be given statin lipid-lowering therapy to reduce the LDL level to below 1.4 mmol/L. Patients with elevated LDL should undergo a comprehensive assessment of risk factors to understand the risk of cardiovascular and cerebrovascular disease, develop a specific treatment plan, and use medication under the guidance of a physician.