Nitroglycerin for the treatment of angina pectoris is metabolized by the body to produce nitric oxide, which is a strong vascular smooth muscle relaxant substance that causes vasodilation. Nitroglycerin dilates blood vessels mainly by dilating small arteries and veins, and the intensity of action is positively correlated with the dose. Clinically, nitroglycerin dilates coronary arteries and dilates small arteries, which plays the role of reducing cardiac preload and effectively increases coronary artery perfusion pressure. When nitroglycerin is used, the patient’s heart rate will increase, causing a reflexive decrease in blood pressure, so it is important to monitor the patient’s blood pressure and heart rate when using nitroglycerin.