Patients with severe hypercholesterolemia and with cardiovascular disease need to take oral atorvastatin 20mg daily. The main effect of atorvastatin is to lower cholesterol, and it also has the effect of stabilizing plaque. The main indication is hypercholesterolemia, and patients with definite cardiovascular and cerebrovascular diseases also need to take it to slow down the progress of atherosclerosis. Atorvastatin 20mg belongs to the commonly used dose, most patients take atorvastatin from 20mg to start, if the condition requires can be increased to 40mg, the higher the dose the more adverse effects. Adverse effects of atorvastatin include stomach upset, nausea, myalgia, elevated liver enzymes, rhabdomyolysis, etc. It is contraindicated in patients with active liver disease, unexplained elevated liver enzymes, and allergy to the drug ingredients. Therefore, it is important to consult a medical professional before using the drug.