Beta-blockers also have some common and serious adverse reactions, most of which are related to their blockade of beta receptors, mainly in seven areas. (1) vascular adverse reactions: bradycardia, atrioventricular block, and heart failure due to excessive dose; (2) asthma: if severe asthma or bronchospasm is prohibited, with acute infection of chronic respiratory disease and must be used, consider the use of highly selective β1 receptor blockers, must start with small doses; (3) the effect on blood lipids: no intrinsic sympathomimetic activity β receptor (3) Effects on blood lipids: non-intrinsic sympathomimetic beta-blockers can increase low-density lipoprotein (LDL-C) and triglycerides, and decrease high-density lipoprotein (HDL-C); (4) Diabetic patients taking glucose-lowering drugs can mask hypoglycemic symptoms; (5) Some special patients, such as smokers with non-selective beta-blockers to lower blood pressure is ineffective, but the switch to highly selective beta1-blockers can significantly improve blood pressure, because (6) Slow heart rate is not an absolute contraindication to β-blockers, as long as the heart rate is above 60 beats, starting with a small dose, closely observed and gradually increased, it can still be applied; (7) Some patients with coronary artery disease cannot apply β-blockers because their heart rate becomes slower after using other drugs that affect the heart rate, and as a result, the patient’s (7) Some patients with coronary artery disease cannot apply beta-blockers because their heart rate becomes slower after using other drugs affecting heart rate, and as a result, the patient’s activity tolerance is very low and there are symptomatic attacks.