Both cardiac pain relief and nitroglycerin belong to nitrate drugs, which can dilate coronary arteries and improve myocardial blood supply, and are used for emergency treatment of coronary heart disease. There are obvious differences between the two, mainly in terms of drug onset time and duration of effect. First, the onset of action of the drug, nitroglycerin has a rapid onset of action, if taken sublingually, it can take effect and function within 1-2 minutes. The onset of action of cardiac pain is relatively longer, even if it is taken sublingually, it takes effect within 5-20 minutes, and if it is taken orally, it takes 15-45 minutes to take effect. Second, duration, the duration of nitroglycerin effect is short, and the effect will disappear after 10-30 minutes. The duration of cardiac pain is relatively long, with the duration of sublingual effect lasting about 45-120 minutes and the duration of oral effect about 2-6 hours. When comparing the two, nitroglycerin focuses on the acute attack of myocardial ischemia, and cardiac pain focuses on the treatment of myocardial ischemia at ordinary times.