Chlamydia infection is a common sexually transmitted infection in humans caused by the bacterium Chlamydia trachomatis. Chlamydia is a major infectious cause of human genital and eye disease. Chlamydia infection is one of the most common sexually transmitted infections worldwide. Chlamydia can be transmitted during vaginal, anal, or oral sex, and can be passed from an infected mother to her baby during childbirth. Chlamydia can usually be effectively treated with antibiotics. More than 95% of people will be cured if they take their antibiotics correctly. Most commonly prescribed antibiotics for chlamydia are azithromycin and doxycycline.