The slowest time for an anal fissure to heal on its own depends on the situation and is related to the length and severity of the fissure and cannot be generalized. An anal fissure is a small ulcer formed by a fissure in the skin layer of the anal canal below the dentate line. Once a patient develops anal fissures, it is easy to cause repeated fissures, from superficial damage to deep muscle damage, and bacteria will gradually invade. In general, patients with anal fissures are unlikely to heal on their own and need to be treated. Patients are advised to consult an anorectal clinic in time to have the local sphincter spasm released by a professional doctor, and to interrupt the vicious cycle by providing pain relief and promoting smooth defecation. In addition, if the patient does not heal after a long time, or if conservative treatment is ineffective and the symptoms are severe, surgical treatment can also be used. Patients with anal fissures are advised to avoid spicy and stimulating foods to avoid constipation and reduce the chance of anal fissures. Also pay attention to timely cleaning of the anus after the stool to keep it clean.