Generally speaking, blood lipid 5.9mmol/L refers to the total cholesterol level, which is relatively high, indicating that there is an abnormally elevated blood lipid index, which may be related to hypercholesterolemia. In general, the specific level of blood lipids can reflect the lipid metabolism in the body. During the blood lipid test, four indicators will be examined: total cholesterol, triglycerides, LDL and HDL, of which the normal value of total cholesterol is about 2.8-5.7 mmol/L. If the actual value reaches 5.9 mmol/L, the blood cholesterol level may be higher than that of total cholesterol. If the actual value reaches 5.9 mmol/L, it means that the total cholesterol index is abnormally high, which may be related to hypercholesterolemia. If it remains untreated, then it may also lead to subsequent problems such as atherosclerosis. Therefore, it is recommended that the patient under the guidance of the doctor for further examination in a timely manner, and according to the results of the examination for targeted treatment, and pay attention to the diet of light, eat more fresh vegetables and fruits, drink more water, so as to promote the total cholesterol index back to normal.