The formation of perianal abscess: 1. to have infectious bacteria: E. coli is the main bacteria in the intestinal tract, so it is also the main infectious bacteria of perianal abscess. 2. to have triggering factors: when physical fatigue, lack of sleep to make resistance decline, or over-eating spicy, drinking alcohol, eating seafood can induce anal sinus infection, forming perianal abscess, its pathogenesis is generally like this: the anal sinus is funnel-shaped. When the anal sinus is infected and inflamed, the inflammation is retrograde to the anal gland along the mouth of the anal gland, causing edema and inflammation of the anal gland, and the inflammation continues to develop, and the glandular tissue invades the surrounding tissue through blood vessels and lymphatic vessels, forming perianal inflammation, which is the first stage of perianal abscess. The early formation of anal fistula is perianal abscess, which is caused by bacteria retained in the anal sinus and is characterized by painful perianal swelling with fever. Perianal abscesses are caused by infection of the anal glands, where bacteria from the anal sinus infect the anal glands through the ducts of the anal glands and cause perianal abscesses, and the so-called anal fistulas are sinus passages where pus is formed. Almost all perianorectal abscesses are transformed into anal fistulas, the symptoms of which are recurrent pus flow around the anus accompanied by fever and pain.