Chlamydia is caused by bacteria which are found in infected semen and vaginal fluids.

Chlamydia symptoms


Symptoms might show within one to three weeks of infection, but around half of men and most women have no symptoms.

Chlamydia in the penis can cause:

  • a whitish, cloudy or watery discharge 
  • pain when urinating
  • pain in the testicles
  • burning or itching in the genital area.

In the vagina, it can cause:

  • a change in the vaginal discharge 
  • pain when urinating 
  • pain in the belly or lower back 
  • pain during sex 
  • bleeding between periods or after sex.

Chlamydia in the throat is usually symptom free.

It generally causes no symptoms in the rectum but might cause discomfort and discharge.

Chlamydia can also be transferred to the eyes, where it can cause conjunctivitis.

How it's passed on


Chlamydia is spread during vaginal, oral or anal sex without condoms. It’s also transmitted on sex toys (unless they are washed or covered with a condom each time they are used on a different person).

It's not yet known whether chlamydia is spread on fingers when you touch an infected part of the body then touch other parts of your or someone else’s body.

Using the male condom or a Femidom (the female condom) cuts the risk. Other types of contraception, such as the contraceptive pill, offer no protection against STIs.

If you have HIV, having untreated chlamydia could make it more likely that you’ll pass on HIV during unprotected sex. But if HIV drugs have made your viral load undetectable then chlamydia or other infections don’t appear to make you more likely to pass on HIV.

Chlamydia tests and treatment


There’s a urine test for chlamydia, or a sample can be taken from the infected part of your body using a swab (small cotton bud).

Swabs only take a few seconds and don’t hurt – they may be uncomfortable for a moment or two.

Chlamydia is treated with antibiotics. Don’t have sex until treatment has finished or you could pass on the infection. If you were given a single dose of antibiotics, you will be asked to wait for a week to have sex.

People you have had sex with also need to get checked – a clinic can contact them if you don’t want to. Untreated chlamydia sometimes causes serious problems, including infertility in men and women.

Most people get tested and treated for infections like chlamydia at sexual health (or GUM) clinics. It's free and confidential – no-one else, including your GP, will be told about your visit. Some GP surgeries also test for and treat these infections.

The more people you have sex with, especially unprotected sex, the more chance there is of catching infections like chlamydia. You can have them without knowing, so regular check-ups are a good idea, especially if you're starting a new relationship and/or you want to stop using condoms with your partner.