Beta-blockers have negative chronotropic and force-changing effects and can cause bradycardia and atrioventricular block, which can induce heart failure or deterioration of cardiac function. They can cause peripheral vasoconstriction, such as cold limbs and intermittent claudication, and can induce bronchial asthma. Beta blockers can cause central nervous system side effects, such as nightmares, insomnia, hallucinations, etc. They can also cause male sexual dysfunction such as impotence. Some β-blockers can affect the body’s sugar and fat metabolism, which can delay the recovery time of hypoglycemia, increase triglycerides and decrease HDL; some can affect liver and kidney function, and should be used with caution for patients with liver and kidney insufficiency. Some reports indicate that beta-blockers can reduce white blood cells and increase blood uric acid. The first dose effect of beta-blockers may also occur, in the first application of beta-blockers, there may be a drop in blood pressure, heart rate slowdown, and even cardiac arrest; and the sudden discontinuation of long-term beta-blockers may induce or aggravate angina pectoris or even myocardial infarction.