Also called

  • STI, STD, sexually transmitted infection, sexually transmitted disease


  • Chlamydia is a very common sexually transmissible infection.
  • If left untreated, chlamydia can cause pelvic inflammatory disease in women, which can lead to chronic pain and infertility. 
  • In men, untreated chlamydia can cause pain and swelling in one or both testicles.
  • If detected early, chlamydia may be treated with a single dose of antibiotics.
  • Partners of people with chlamydia also need to be informed, tested and treated as they may be infected too. If so, there is a risk they could reinfect the person who has been treated for chlamydia.

Chlamydia is caused by the bacterium Chlamydia trachomatis and is a very common sexually transmissible infection (STI). It is often called the ‘silent infection’ because most people do not realise they have it. It can affect women and men of all ages, but most frequently occurs in people who are under 25 years of age due to a higher rate of partner change. 

Chlamydia is spread by having sex of any kind with an infected person and not using a condom. 

Symptoms of chlamydia in women

Most women who are infected have no signs or symptoms of chlamydia. However, it can infect the cervix and spread to the uterus and fallopian tubes, causing pelvic inflammatory disease (PID), chronic pelvic pain, ectopic pregnancy and infertility. 

If a woman is pregnant and has chlamydia, it can be passed on to a baby during birth, causing lung or eye infections.

In women, if symptoms are present, they may include: 

  • unusual vaginal discharge
  • burning feeling when urinating
  • pain during sex
  • bleeding or spotting between periods
  • bleeding after sex
  • lower abdominal pain.

Symptoms of chlamydia in men

Men who have chlamydia usually do not have any signs or symptoms. In men, chlamydia infects the urethra and may spread to the epididymis – the tube that carries sperm from the testicles. 

In men, if symptoms are present, they may include: 

  • discharge from the penis
  • discomfort when urinating
  • sore, swollen testes.

Diagnosis of chlamydia

Chlamydia is an easily diagnosed and curable STI. Tests are painless and usually involve a simple urine test. Alternatively, a cotton swab may be used to test for chlamydia from the vagina, cervix, anus or penis. The specimen is then sent to a laboratory for testing.

Chlamydia is spread through ‘unsafe’ sex

Chlamydia is spread when a person has sex with an infected person and does not use a condom. Because chlamydial infection often has no symptoms, many people do not realise they have the infection. Even if you know a person well, you may not be able to tell they have an STI, because people can look healthy and still have chlamydia. 

Remember, you can get chlamydia and other STIs from a new sexual partner who has had sex with an earlier infected partner. It can also be spread from a long-term partner who has had sex with other people. 

Chlamydia check-ups

An annual chlamydia check-up is highly recommended if you are sexually active and under 25 years of age. You should check for chlamydia more frequently if you change partners very frequently. Any sexually active person can get chlamydia, but you are at greater risk if you have sex without a condom or if you have multiple sexual partners. 

Treatment for chlamydia

If detected early, chlamydia can be treated with a single dose of antibiotic. If complications from chlamydia infection are present, such as pelvic inflammatory disease in women, a longer course of antibiotics will be required. 

If you have chlamydia, your sexual partner(s) also needs to be informed, tested and treated, as they may be infected too. If so, they could reinfect you if they are not treated as well. It is recommended that have another test for chlamydia three months after you are treated to make sure you have not been re-infected. 

If you are not sure that your sexual partner(s) will seek treatment, then you can ask for extra medication (or a prescription) to give to them so that they can be treated as soon as possible. This is known as patient delivered partner therapy (PDPT).

The antibiotic (azithromycin) used to treat chlamydia is safe and almost 100 per cent effective when used as directed.

Prevention of chlamydia

Safe sex practices reduce the risk of STI transmission. Using condoms and dams during vaginal and anal sex creates a protective barrier against getting chlamydia, as well as other STIs.

Condoms for men can be bought from supermarkets, pharmacists and other outlets. (Latex-free condoms are also available from some outlets.) Male condoms and lubricant are available free from the Melbourne Sexual Health Centre.

Female condoms and dams are available through Family Planning Victoria and are available free from the Melbourne Sexual Health Centre, on request. They are also available from selected shops. 

Where to get help


More information

Sexually transmissible infections

The following content is displayed as Tabs. Once you have activated a link navigate to the end of the list to view its associated content. The activated link is defined as Active Tab

Content Partner

This page has been produced in consultation with and approved by: Melbourne Sexual Health Centre

Last updated: June 2020

Content on this website is provided for information purposes only. Information about a therapy, service, product or treatment does not in any way endorse or support such therapy, service, product or treatment and is not intended to replace advice from your doctor or other registered health professional. The information and materials contained on this website are not intended to constitute a comprehensive guide concerning all aspects of the therapy, product or treatment described on the website. All users are urged to always seek advice from a registered health care professional for diagnosis and answers to their medical questions and to ascertain whether the particular therapy, service, product or treatment described on the website is suitable in their circumstances. The State of Victoria and the Department of Health & Human Services shall not bear any liability for reliance by any user on the materials contained on this website.