Angina pectoris is an acute attack symptom caused by coronary artery atherosclerosis, which narrows myocardial blood vessels and reduces blood flow, and can be triggered by exertion, exercise, emotional stress, straining to defecate and other conditions that increase the burden on the heart. During an angina attack, the patient will suddenly feel a continuous crushing or suffocating pain under the sternum. The patient should immediately stop all activities, calm down, stand and rest on the spot, without lying down, so as not to increase the amount of blood return and thus increase the burden on the heart. Immediately take out the first aid medicine with you, such as a nitroglycerin tablet, chew it up and put it under the tongue, usually the pain can be relieved in about two minutes. If the effect is not good, after 10 minutes, you can take another piece under the tongue to increase the amount of medicine. However, it is important to note that it is not advisable to take more than three nitroglycerin tablets in a row, regardless of whether the angina is relieved, or if there is another attack. If the pain is severe or if you have isoamyl nitrite with you, you can crush it in a handkerchief and inhale it close to your nostrils, usually in 10-20 seconds after inhalation. Both of these drugs are fast-acting vasodilators. The effect of isoamyl nitrite is faster and stronger, but the time to maintain the effect is short, only 7-8 minutes; while nitroglycerin tablets can maintain the effect up to 30 minutes. Because of the strong vasodilating effect of isoamyl nitrite, transient hypotension may occur after the drug is administered. In order to prevent unpredictability, you should sit down and rest immediately after the medication takes effect. However, patients who have glaucoma at the same time should not take either of these drugs, otherwise they may cause severe eye pain, headache, blurred vision or even blindness due to increased intraocular pressure. For patients with coronary artery disease who have their first sudden onset of angina, they can be hidden in extreme panic due to the sudden and severe pain in the heart. This is very detrimental to the relief of angina pectoris. The panic will significantly accelerate the heart rate, thus increasing the burden on the heart. Patients with first-onset angina often do not carry emergency drugs with them, and in this case, there is no need to worry too much about the danger, most of the angina attack lasts less than 10 minutes, while those who have myocardial infarction have a history of frequent attacks. When there is no medicine, stopping activities and resting on the spot to keep a calm mind is the most effective first aid measure.