Chlamydia vaginitis is a common sexually transmitted disease (STD) and the main pathogen is Chlamydia trachomatis. Chlamydia trachomatis infection is the first sexually transmitted disease in developed countries, and the rate of Chlamydia trachomatis infection is increasing in China. Chlamydia trachomatis mainly infects the columnar epithelium and migratory epithelium without invading to the deeper layers, which can cause cervical mucositis, endometritis, tubal inflammation and eventually lead to infertility. The transmission route of Chlamydia is mainly through sexual transmission, but rarely indirectly through contact with the patient’s secretions contaminated items. 2. Clinical manifestations The incubation period is 13 weeks and occurs mostly in sexually active people. The cervical canal is the most common site of infection for chlamydia, and 70% to 90% of chlamydial mucositis has no clinical symptoms. If symptoms are present, they may include increased vaginal discharge, mucopurulent, post-coital or intermenstrual bleeding. Difficulty in urination, urgency and frequency of urination may occur if accompanied by urethritis. Examination reveals purulent discharge from the cervical canal, redness and swelling of the cervix, and increased mucosal fragility. 3, diagnosis Chlamydia trachomatis culture is the gold standard for the diagnosis of Chlamydia trachomatis infection, with high sensitivity and specificity. 4.Treatment Doxycycline 100 mg/bid times for 7 days, or azithromycin 1 g in a single dose. Alternative regimens: erythromycin 500 mg 4 times daily for 7 days; erythromycin 800 mg 4 times daily for 7 days; ofloxacin 300 mg/bid for 7 days; or levofloxacin 500 mg/qd for 7 days. Sexual partners should be examined and treated at the same time during treatment. 5. Chlamydia infection in pregnancy Chlamydia infection can cause premature birth, stillbirth, low birth weight baby, neonatal meningitis, etc. Pregnant women at high risk of Chlamydia trachomatis infection should be screened and treated if the infection is found. The preferred treatment is azithromycin 1 g or amoxicillin 500 mg/tid orally for 7 days. Doxycycline, quinolones and tetracycline are contraindicated in pregnant women. Retest for chlamydia after 3 to 4 weeks of treatment.