The main reasons for the splitting of the posterior anal groove are: 1. Hemorrhoids caused by the anal opening, hemorrhoids are perianal rectal mucosa constantly flexing and circling the formation of venous masses, when eating spicy, irritating food, or after stir-frying put too much seasoning. The main reason for this is that these things can not be fully absorbed by the gastrointestinal tract, and when discharged with the stool will stimulate the perianal hemorrhoids, leading to painful fissures in the posterior groove of the anus. 2, anal fissures, constipation and other diseases caused by the usual bad eating habits or do not love to drink water, resulting in dry stools, these dry stools in the discharge will constantly stimulate the anal opening leading to fissures in the posterior groove. 3, perianal abscess, anal fistula, etc. These diseases can form one pus cavity and fistula after another at the anal opening. When the body is stimulated by inflammation or fire, after drinking alcohol will lead to this phenomenon.