[Pathogen] Caused by Chlamydia trachomatis serotypes Ll, L2, and 13, and humans are the natural host of Chlamydia trachomatis. [Route of infection] mainly through sexual intercourse, occasionally through contact with the patient’s secretions, or through oral and anal sex transmission. [Clinical manifestations] 1, incubation period of 5-21 days, an average of 7-10 days. 2. Preferred sites: penile body, coronal groove, foreskin and glans in men; labia majora and minora, vestibule, vaginal orifice and urethra in women. 3, lesion characteristics: early superficial ulcers, single or multiple, no obvious conscious symptoms, self-healing after a few days, without scarring, 1-4 weeks later, most male Si appear unilateral inguinal lymph node enlargement, known as the fourth venereal disease cross-craft, lymph nodes can break pus, healing after a few months to form scars, women in addition to inguinal lymph node enlargement, but also often cause rectal and rectal Peripheral inflammation, long-term inflammation can lead to rectal stenosis. 4, systemic symptoms: in the occurrence of lymphadenitis, patients have fever, chills, arthralgia and other symptoms. [Laboratory tests] 1. Serological tests: complement binding test, immunofluorescence test, etc. 2.Chlamydia culture. [Treatment] 1.Doxycycline: 100m8, 2 times a day for 21 days. 2.Tetracycline: 500mg, 4 times a day for 21 days. 3.Erythromycin: 500mg, 4 times a day for 14 days. 4.Compound Synthroid: 1.0mg, 2 times a day for 14 days.