Chlamydia is a common sexually transmitted infection caused by a bacterium called Chlamydia trachomatis. It can occur in both men and women and is usually transmitted through vaginal, oral, and anal sex. It is easily treated and cured with antibiotics.

Chlamydia infection is often asymptomatic, so regular testing is important. If not treated, chlamydia can cause serious problems, especially in women, including pelvic inflammatory disease, infertility, and ectopic pregnancy. In pregnant women, it can cause preterm birth.