Pelvic inflammatory disease, abbreviated as PID, refers to a group of infectious diseases of the upper female reproductive tract, mainly including endometritis, tubal inflammation, tubo-ovarian abscess, and pelvic peritonitis. Its clinical manifestations can vary in symptoms and signs depending on the severity of inflammation and the extent of involvement. In mild cases, the symptoms are asymptomatic or mild, manifested only by increased vaginal discharge and lower abdominal cramping or mild pain. In severe cases, there is persistent lower abdominal pain, which is aggravated after activity or sexual intercourse, fever or even high fever, chills, headache and lack of appetite. The onset of menstruation presents with increased menstrual flow and prolonged periods. In case of peritonitis, gastrointestinal symptoms such as nausea, vomiting, abdominal distension and diarrhea appear. If there is urinary tract infection, symptoms such as urinary frequency, urinary urgency and painful urination appear. In case of abscess formation, a mass in the lower abdomen may be found and symptoms of local pressure and irritation may occur; the mass may cause difficulty in urination and frequent urination when it compresses the bladder; a mass located outside the peritoneum may cause diarrhea, a feeling of urgency and difficulty in defecation. Patients’ signs vary widely, with no obvious abnormal findings in mild cases, or gynecological examination only revealing painful cervical lifting or uterine body pressure or painful pressure in the adnexal area. In severe cases, there is an acute appearance with elevated body temperature, increased heart rate, pressure pain, rebound pain and muscle tension in the lower abdomen, and even abdominal distention and disappearance or weakening of bowel sounds. Since clinical symptoms and signs of pelvic inflammatory diseases vary widely and the accuracy of clinical diagnosis is not high (65-90%), antibiotic treatment should be given as long as the minimum diagnostic criteria (cervical lifting pain or uterine pressure pain or adnexal area pressure pain) are met and other factors causing lower abdominal pain are excluded.