Nitroglycerin ointment can be used for the treatment of anal fissure with the relief of pain caused by anal fissure. Nitroglycerin is metabolized in smooth muscle and vascular endothelial cells to release nitric oxide, which acts as an endothelial diastolic factor that relaxes smooth muscle. Local application of nitroglycerin in the anal canal can relax the anal sphincter, alleviate spasm, alleviate symptoms, relax intravascular smooth muscle, diastole blood vessels, increase the blood supply of the vascular localization, and promote the healing of ulcers. Pregnant and lactating women should be cautious, children younger than 18 years of age should be prohibited, there is no specific report on the use of the drug in elderly patients. Adverse reactions such as headache, dizziness, nausea and vomiting, blurred vision, fatigue, rectal bleeding, and worsening of angina chest pain can occur. In addition, it is contraindicated in patients with hypersensitivity to nitrates, aortic stenosis, hypotension, hypovolemia, cardiac valve stenosis, myocardial anomalous proliferative heart disease, brain injury, pericarditis, postural hypotension, cerebral hemorrhage, pericardial effusion, severe anemia, -cerebral insufficiency of blood supply, angle-closure glaucoma, and migraine headache. Use with caution in severe hepatic and renal disease disorders, angina pectoris, heart failure. If you need to use nitroglycerin cream, it is recommended to use it under the guidance of a doctor, do not use the drug without authorization to avoid adverse reactions.