Nitroglycerin ointment is one of the commonly used medications for the initial treatment of anal fissures. Its main effect is to reduce anal resting pressure, diastole blood vessels, improve blood supply to the anal canal and promote healing of anal fissure. In general, most patients (about 75%) are spared from surgery. Its main disadvantages are adverse reactions, such as headache, upright hypertension, inability to control anal excretion and burning sensation, etc., and poor compliance, longer course of treatment, higher recurrence rate, and poorer efficacy for chronic anal fissure with complications (sentinel hemorrhoids, dermatomal external hemorrhoids, and anal papillae hypertrophy).