There is no uniform theory of how long it takes to cure anal fissures with nitroglycerin ointment, but it must be judged by the patient’s application of the drug, which usually takes 2 months to cure anal fissures better. Nitroglycerin ointment is mainly used to treat anal fissures and relieve pain caused by fissures. When applied locally, the drug can relax the anal canal sphincter, relieve spasm and reduce symptoms, as well as relax smooth muscle in blood vessels, relax blood vessels, increase blood scale in blood vessels and promote healing of ulcers. This drug has been shown in clinical studies to be effective in relieving anal fissures and fissure-related pain. The study was also conducted over a 2-month period and the group using nitroglycerin ointment after 2 months showed a significant decrease in anal fissure pain scores and a significantly higher degree of anal fissure relief than the control group. In the case of old fissures, many of the fissures have formed chronic ulcers and are surrounded by fibrosis, so nitroglycerin does not heal the fissures, but only controls the symptoms.