The causes of sore and swollen buttocks with the feeling of defecation include proctitis, perianal abscess, etc. The treatments include medication such as antibiotics and surgery. 1. Proctitis: Diarrhea and increased rectal secretions caused by proctitis can stimulate the buttock muscles, resulting in a feeling of soreness and swelling in the buttocks. Treatment includes medication such as mesalazine, rituximab, metronidazole, budesonide, etc. If the condition is serious, it can be treated by surgery, such as total proctocolectomy with ileal storage pouch and anal canal anastomosis. 2. Perianal abscess: Perianal abscess refers to the acute purulent infections occurring in the anorectal canal and its surrounding tissues, the lesion of the abscess increases in size, pressure symptoms, ulceration, etc. will lead to swelling and soreness in the buttocks. Drug treatment such as cefixime, celecoxib, etc., the main treatment mode for surgical treatment, such as abscess incision and drainage. The choice of medication needs to be made under the guidance of a doctor. When patients experience discomfort, they should go to the hospital immediately.