Chlamydia is a very common sexually transmitted infection. Chlamydia infects the mucous membranes (linings) of the male urethra, female cervix and sometimes the eye, rectum or throat.
Chlamydia is transmitted by having vaginal, anal or oral sex with someone who has the infection.
Chlamydia can also be passed from mother to baby during birth. The baby may develop eye or lung infections.


Most women will not develop symptoms, but can still pass it on to others. Possible symptoms in women include: a change in vaginal secretions, lower abdominal pain or abnormal vaginal bleeding.
Men may have a discharge, pain on urinating, penile irritation or testicular pain which develops 2-4 weeks after having unprotected sex with an infected partner. There may not be much discharge, often only slightly watery discharge in the morning. About 25% of men have no symptoms, but can still pass it on.

In both sexes, the infection can go away without treatment, but can also remain for months or even years.


Chlamydia testing is done by swab or urine sample. Test results usually take 2-3 days.


Chlamydia is easily cured with antibiotics. Single-dose treatment is now easily available. Sexual partners should have a sexual health check and treatment for Chlamydia even if they have no symptoms and even if they have a negative test result.

Possible complications

Chlamydia can cause pelvic inflammatory disease (PID). This is when the uterus and fallopian tubes become inflamed. PID may have no symptoms, but some women develop lower abdominal pain, vaginal discharge and bleeding. PID causes scarring of the fallopian tubes, which leads to ectopic pregnancy, infertility or chronic pelvic pain.
Men may develop infection of the epididymis and testicles. Chlamydia may cause infertility in men.
Chlamydia may trigger Reiter’s syndrome (arthritis, rashes and eye inflammation).

This page was last updated at 12:00PM on February 18, 2019.