Erythromycin ointment can certainly be used for anal fissures. Erythromycin ointment has an anti-inflammatory effect and is used in the initial stage when the fissure is shallow and the infection is not serious. One, it can reduce the local inflammatory reaction of the fissure; two, it can promote the healing of the fissure. Most anal fissures are caused by constipation and dry stools, so patients with anal fissures must pay attention to a light diet and avoid spicy and irritating foods during the attack. It is important to eat more vegetables, fruits and other coarse fiber foods, and drink more water to keep the stool soft and clear to prevent constipation. It should be noted that anal fissures with a history of more than 3 months are called old anal fissures and may also be accompanied by the anal fissure triad, which is the sentinel hemorrhoid outside the anus, the chronic ulcerated fissure in the middle and the enlarged anal papilla inside. Conservative treatment with medication is not effective and surgical treatment needs to be considered.