Acute appendicitis is the most common acute abdominal condition in abdominal surgery. In acute suppurative, gangrenous appendicitis or perforated appendix that is not treated surgically in a timely manner; or if surgical treatment is slightly delayed due to atypical symptoms; the greater omentum in the upper abdomen moves down to the area of the right lower abdomen where the appendix is located encasing the inflamed appendix and its surrounding tissues and an inflammatory mass or abscess is formed. The manifestation is a full, poorly defined, locally painful mass that can be palpated in the right lower abdomen; CT and ultrasound show a thickened appendix, sometimes a fecal stone of the appendix, surrounding exudative changes, inflammatory masses and fluid dark areas of abscesses. This is an active defense response of the body to inflammation, which aims to confine the inflammation and prevent its diffusion in the abdominal cavity. The treatment of periappendiceal abscesses is carried out following the principles of evidence-based medicine. Evidence-based medicine differs from conventional medicine in that it places greater emphasis on the fact that any medical decision should be based on the best scientific research evidence. In layman’s terms, this means individualized treatment based on close observation of changes in the disease, tailored to the individual and the disease. If the onset of the disease is short (usually within 3-5 days), surgical treatment can be performed as acute appendicitis, and in most cases the appendix can be found and routinely removed, with local drainage of the pus (local drainage tubes are required). If the onset of the disease is too long (more than 5 days), the inflammation is limited to the right lower abdomen, the patient’s blood leukocyte count and neutrophils are not too high and the patient only has a low fever, surgery is not needed and conservative treatment with antibiotic therapy can be continued, and in most patients the abscess can be reduced in a short time until it is absorbed. If the inflammatory mass in the right lower abdomen is increasing, the local pressure pain is widening, and there is a tendency for the inflammation to diffuse; the patient’s systemic inflammatory symptoms are worsening, the total white blood cell count and neutrophil classification are rising, and the original abscess is enlarging on CT and ultrasound review, then surgery is needed. However, the main purpose of surgery at this time is to drain the pus (intraoperative placement of drainage tubes), not to remove the appendix, which is difficult to find at this time and can be removed at an elective stage. As for abscesses found in other parts of the abdominal cavity due to appendicitis after surgery, they can be solved by ultrasound-guided puncture and drainage.