This condition is called anal fissure, which is mainly caused by dry stools. The main way to treat anal fissures is to keep the stool open. You can eat more laxative and fiber containing vegetables and fruits such as celery, dried aromatic vegetables, green leafy vegetables, peanuts, sesame seeds, nuts, bananas, dragon fruit, snowdrops and so on. In case of stubborn constipation, you can also take oral and laxative herbal medicines to keep the stool open. On the basis of keeping the bowels open, you can use topical medications such as erythromycin ointment and Ma Yinglong hemorrhoid cream to apply topically to the wound to promote the healing of the fissure. If the wound does not heal after a period of time with topical medication and you feel special pain, then you can consider surgical treatment, using anal dilation, lateral incision, anal sphincter picking, etc. to enlarge the anus so that the stool can be easily discharged.