Indications for nitroglycerin include the treatment or prevention of angina pectoris and as a vasodilator for the treatment of congestive heart failure. Nitroglycerin can be taken regularly, but it is important to note that long-term application of nitroglycerin may result in drug resistance. Long-term application here means one day, if the pump of nitroglycerin is administered intravenously to maintain 24 hours, tolerance to nitroglycerin may develop at this time. So nitroglycerin is recommended to be taken in divided doses rather than the method of intravenous maintenance all the time. Nitroglycerin can not only dilate the smooth muscle of blood vessels, reduce peripheral resistance, reduce the amount of return blood, and reduce myocardial oxygen consumption, thus relieving angina pectoris, but also promote the formation of collateral circulation, which has a very significant effect on the treatment of angina pectoris.