Both perianal abscesses and fistulas are purulent infections of the soft tissues surrounding the anorectum and generally originate from an infection of the anal glands. The anal glands open in the anal sinus at the junction of the anus and the rectum and secrete mucus that lubricates the rectum and the mucosa of the anal canal during the passage of stool. The opening of the anal sinus is upward and can easily accumulate stool and form inflammation. Bacteria can enter the anal gland through the opening of the anal gland, and further development can lead to infection and suppuration of the perianal soft tissue. The acute stage of this infection and septicemia is characterized by persistent and severe pain around the anus, and in severe cases, the inability to walk or sit. Redness and swelling around the anus can be seen, and tenderness is evident, and the patient may become febrile. This acute stage of infection is called perianal abscess. If the abscess breaks down, the pus flows out and the pain is relieved, the pus will flow repeatedly for a long time afterwards, and then a long-term chronic infection will be formed, and this period is called anal fistula. From the etiology, it is easy to find that the source of this infection comes from the anal sinus in the rectum, the opening of the anal gland, which we call the “internal port”; and the opening on the skin after the abscess breaks down is called the “external port”. Both perianal abscesses and fistulas require surgery to heal, and the key to surgery is to remove the cause of the disease, i.e., to deal with the “internal orifice”. During surgery, the internal orifice needs to be found and incised as much as possible, and the incision needs to be open and well drained. If the abscess or fistula is deep, direct incision may damage the anal sphincter and cause anal incontinence, and a thread will need to be hung to achieve unobstructed drainage.