The main ingredient of Lipitor is atorvastatin calcium tablets, which are recommended to be taken once a day at a fixed time, with the best effect at bedtime. Lipitor is commonly used in the treatment of hyperlipidemia and improvement of atherosclerosis in patients with cardiovascular and cerebrovascular diseases. Patients usually take the drug for about 7 days, the total cholesterol and LDL in the blood can be decreased, and HDL can be increased, and the maximum effect can be achieved after one month. Since the synthesis of cholesterol in human body has a regularity, i.e. circadian rhythm, and the synthesis of cholesterol depends on the activity of HMG-CoA reductase, with the lowest activity at noon, the higher activity from midnight to early morning, and the highest activity at 12 o’clock at night, taking Lipitor at bedtime can make the concentration of the drug reach its peak at night, thus maximizing the reduction of cholesterol synthesis. In addition, patients should have a meat and vegetable dinner while taking the drug, and should not be overfed. It is recommended to adjust the cooking oil to phytosterol corn oil, which can be controlled at 25-30g per day to reduce total cholesterol and LDL cholesterol.