Medibank Health Directory

What is chlamydia?

Chlamydia is a very common sexually transmitted infection (STI), passed from one person to another through unprotected sex.

It is most common in young people (15-29 years). Caused by the bacterium Chlamydia trachomatis, it affects the urethra, throat and anus. Many people don’t experience any symptoms of chlamydia. Once diagnosed, it is easily treatable with antibiotics.

Sometimes called ‘the silent STI’ – because it often has no symptoms. Research shows that 50% of men and 70-80% of women don't get symptoms at all with a chlamydia infection. Chlamydia is easily transferred from one person to another during unprotected sex.

Chlamydia can become serious for both men and women. If left untreated, chlamydia can lead to serious complications such as infertility, ectopic pregnancy, prostatitis or epididymitis. Pregnant women can pass it on to unborn babies, with serious consequences. If you have chlamydia, it’s also easier to catch HIV.

Chlamydia is most common in young people, and those who have had more than one sexual partner in the last 12 months. You’re also more likely to get chlamydia if you don’t use condoms, or if you or your partner has another STI.

If you suspect you have chlamydia, you should get tested early and then, if required, start treatment. Diagnosis is made by a simple urine test or cotton swab. Treatment of chlamydia typically involves a course of antibiotics.

To avoid chlamydia and other STIs, it’s important to practice safe sex which includes use of condoms or other barrier methods of contraception, limit the number of sexual partners you have, and know the history of your sexual partners. If you are sexually active, you should have regular STI checks.

Symptoms of chlamydia

Women, in particular, are less likely to notice symptoms of chlamydia. However, some will experience:

  • Burning pain when passing urine.
  • Unusual vaginal discharge.
  • Pain in the lower belly or during sex.
  • Spotting between periods or after sex.

Men may experience symptoms of chlamydia including:

  • White or yellow discharge from the penis or anus.
  • Burning pain when passing urine.
  • Pain in the opening of the penis.
  • Swollen and sore testes.

Causes and treatment of chlamydia

Chlamydia is caused by the transmission of the bacterium Chlamydia trachomatis from one person to another during unprotected sex. 

Chlamydia is treated with a course of antibiotics. It’s important to remember to take the full course of antibiotics, and don’t drink alcohol while completing the course. 

Your doctor may also advise that you are screened for other STIs; and that your partner is tested and treated for chlamydia, too. 

Further information and sources



This article is of a general nature only. You should always seek medical advice if you think you may have the symptoms of chlamydia.