LDL cholesterol of 3.9mmol/L is normal high, for normal people can not take drugs temporarily, but for people with coronary heart disease, need to take drugs. The normal reference value of LDL cholesterol is 0-3.4mmol/L. For people who do not have coronary heart disease and related risk factors, they can temporarily take no medication and use diet and exercise to lower LDL cholesterol. Eat a light diet with foods that are not high in fat, such as tenderloin, fish, shrimp, etc. Eat more vegetables and fruits, and do not eat fried foods or animal offal. For people with coronary heart disease or related risk factors, medication is needed. Because high levels of LDL cholesterol is one of the risk factors for atherosclerosis, lowering LDL cholesterol is an important means of prevention and treatment of coronary heart disease. Commonly used statin drug therapy, such as atorvastatin, resuvastatin and so on. Common side effects of this type of drug include liver function impairment, abnormal muscle enzymes, etc. Liver function and creatine phosphokinase need to be monitored after taking them. LDL cholesterol is considered to be bad cholesterol. If elevated LDL cholesterol is found, it is recommended to go to a regular hospital to screen for coronary heart disease and related risk factors, and to treat the condition under the guidance of a doctor, and self-diagnosis and treatment should be avoided.