A large painful bag on the buttocks may be caused by local hair follicle infection, or it may be caused by perianal abscess or other diseases, and there are often different treatment measures for different causes. 1. Local hair follicle infection: When a large bag appears, a boil may have formed, and the symptoms are mainly redness, swelling, heat and pain, and white pus spots may appear on the bag, and severe cases may have fever and other discomfort. Patients should first of all pay attention to not sitting for a long time to avoid causing local compression, which may cause the boil to break and aggravate the infection; they can use local antibiotic ointment, such as mupirocin ointment, fusidic acid ointment to apply local treatment, and those who form local abscesses must be promptly incised and drained, and given intravenous antibiotics; 2. Perianal abscess: large packets usually grow around the anus and belong to acute purulent infectious diseases, mostly from anal saphenous infection, a few secondary to AIDS, tumor, trauma, Crohn’s disease, etc. Medication usually requires cephalosporin antibiotics of second generation or higher, together with anti-anaerobic drugs such as metronidazole. When pain occurs, patients should avoid squeezing, long sitting, and frequent touching to prevent aggravating symptoms. If the pain is severe and seriously affects rest, it is recommended to do two-way isobaric drainage surgery for treatment. In addition, herpes simplex, herpes zoster, sebaceous cysts, etc. can also appear on the buttocks with the symptoms of growing bags, but generally accompanied by other corresponding signs, need to be identified in a timely manner, the patient to perform targeted treatment.