Chlamydia is one of the most common sexually transmitted infections (STIs). It’s very easy to treat and cure.

If left untreated it can cause painful complications and serious health problems such as pain in the testicles in men, and pelvic pain and even infertility in women.

A lot of people with chlamydia don’t get any noticeable signs or symptoms of the infection.

This page gives you information about chlamydia, what you can do if you might have the infection, and advice on how to protect yourself and your partners.

Chlamydia (PDF)

It’s caused by bacteria (tiny, living cells) called Chlamydia trachomatis. They can live in the uterus (womb), vagina and cervix (entrance to the womb), the urethra (tube where urine comes out), the rectum (back passage), and sometimes the throat and eyes. Anyone who’s sexually active can get it and pass it on. You don’t need to have lots of sexual partners.

Chlamydia is usually passed from one person to another through sexual contact. You can get the infection if you come into contact with the semen (cum or pre-cum) or vaginal fluids of someone who has chlamydia. Chlamydia is most commonly spread through:

  • unprotected (without a condom) vaginal or
  • anal sex
  • sharing sex toys that aren’t washed or covered with a new condom each time they’re used.

It can be spread by giving or receiving oral sex (going down, giving head) with someone who has chlamydia. The risk can be lowered by using a condom or dam (latex or soft plastic square) to cover the genitals.


If infected semen or vaginal fluid comes into contact with the eye (for example if it’s transferred from the genitals to the eye by the fingers) it can cause conjunctivitis (infection or irritation of the eye). Chlamydia can be passed from a pregnant woman to her baby (see What happens if I get chlamydia when I'm pregnant?).


It’s not clear if chlamydia can be spread by transferring infected semen or vaginal fluid to another person’s genitals on the fingers or through rubbing vulvas (female genitals) together.


You can’t get chlamydia from kissing, hugging, sharing baths or towels, swimming pools, toilet seats or from sharing cups, plates or cutlery.


More than two in three women and one in two men with chlamydia won’t have any obvious signs or symptoms, or will have symptoms so mild they’re not noticed.


Signs and symptoms can show up 1–3 weeks after coming into contact with chlamydia, many months later, or not until the infection spreads to other parts of your body. You might notice:



  • bleeding between periods and/or heavier periods (including women who are using hormonal contraception)
  • bleeding after sex
  • pain and/or bleeding when you have sex  
  • lower abdominal pain (pelvic pain) 
  • an unusual vaginal discharge  
  • pain when passing urine



  • a white/cloudy or watery discharge from the tip of the penis
  • pain when passing urine
  • pain in the testicles.


Men and women


There are rarely any symptoms if the infection is in the rectum (back passage) but it may cause discomfort and discharge.


Infection in the eyes can cause pain, swelling, irritation and/or discharge.


Infection in the throat is uncommon and usually has no symptoms.

You can only be certain you have chlamydia if you have a test.


Anyone can get chlamydia, including people who’ve only had one sexual partner in the last year. You’re more likely to have it if you’re under 25, have a new sexual partner, or more than one sexual partner in the last year, and if you haven’t used condoms.


You should have a test if:

  • you, or a partner, have or think you might have symptoms
  • you’ve recently had unprotected sex with a new partner
  • you, or a partner, have had unprotected sex with other partners
  • during a vaginal examination your doctor or nurse says that the cells of the cervix are inflamed or there is a discharge
  • a sexual partner tells you they have a sexually transmitted infection
  • you have another sexually transmitted infection.


You could still have chlamydia even if a partner has tested negative. The only way to make sure you don’t have chlamydia is to get tested yourself.


If you have chlamydia you’ll be encouraged to be tested for other sexually transmitted infections as you can have more than one sexually transmitted infection at the same time.

It’s important not to delay going for a test if you think you might have chlamydia. A test can be carried out straight away but you may be advised to have another test two weeks after having sex. You can have a test for chlamydia even if there are no symptoms.


  • You may be asked to use a swab yourself around the inside of your vagina.
  • A doctor or nurse may take a swab during an internal examination of your vagina and cervix (entrance to the womb).



  • You may be asked to provide a urine sample. Before having this test you may be advised not to pass urine for 1–2 hours.
  • A doctor or nurse may use a swab around the entrance of the urethra (tube where urine comes out).


Men and women

  • If you’ve had anal or oral sex the doctor or nurse may swab your rectum (back passage) or throat (you may be given the option to do your own tests). These swabs are only routinely recommended for men who’ve had sex with men, and women with anal symptoms.
  • If you have symptoms of conjunctivitis (an eye infection) then a swab of the discharge may be taken.


A swab looks a bit like a cotton bud but is smaller and rounded. It’s wiped over the parts of the body that could be infected and easily picks up samples of discharge and cells. This only takes a few seconds and isn’t painful, though it may be uncomfortable for a moment.


Cervical screening tests and routine blood tests don’t detect chlamydia. If you’re not sure whether you’ve been tested for chlamydia, just ask

The accuracy of a chlamydia test depends on the kind of test used and the type of sample that’s collected. The recommended tests are over 95% accurate in picking up chlamydia. As no test is 100% accurate there’s a small chance that the test will give a negative result when you do have the infection. This is known as a false negative result. This can sometimes explain why you might get a different result when you go to a different clinic to have another test or why you and a partner might get a different test result.


It’s possible for the test to be positive if you haven’t got chlamydia, but this is rare. 

There are a number of services you can go to. Choose the one you feel most comfortable with.


A chlamydia test can be done at:

  • a genitourinary medicine (GUM) or sexual health clinic
  • your general practice
  • contraception and young people’s clinics
  • some pharmacies.


Abortion clinics, antenatal services and some gynaecology services may also offer women a test.


In England local councils pay for free testing for all sexually active men and women under the age of 25 in their area as part of the National Chlamydia Screening Programme.


Some local councils will also provide outreach testing which can be available from places such as colleges, youth clubs, military bases, and other convenient places. The screening programme is usually advertised locally.


In some areas you can order a free self-sampling kit online to do at home. See


It's also possible to buy a chlamydia test to do at home. The accuracy of these tests varies. Some types are very accurate when carried out according to the instructions, others can be less reliable. If you buy a testing kit make sure you get advice from a pharmacist or your doctor.


You can also choose to pay for a chlamydia test at a private clinic.

All tests are free through NHS services and the National Chlamydia Screening Programme. Treatment is also free but if you go to your general practice you may have to pay a prescription charge for treatment.

Chlamydia is treated with antibiotics. If you take the treatment according to instructions, it’s over 95% effective at treating genital chlamydia.

  • You’ll be given antibiotic tablets either as a single dose or a longer course (up to two weeks).
  • If there’s a high chance you have the infection, treatment may be started before the results of the test are back. You’ll always be given treatment if a sexual partner is found to have chlamydia.
  • You may also need other treatment if complications have occurred.
  • Do tell the doctor or nurse if you’re pregnant, or think you might be, or you’re breastfeeding. This may affect the type of antibiotic that you’re given.
  • There is currently no evidence that complementary therapies can cure chlamydia.

You should notice an improvement quite quickly after having treatment.

  • Discharge or pain when you urinate should improve within a week.
  • Bleeding between periods or heavier periods should improve by your next period.
  • Pelvic pain and pain in the testicles should start to improve quickly but may take up to two weeks to go away.

If you have pelvic pain or painful sex that doesn’t improve, see your doctor or nurse as it may be necessary to have some further treatment or investigate other possible causes of the pain.

If you take the treatment according to the instructions you won’t normally need a follow-up test. However, you should go back to the service if:

  • you think you may have come into contact with chlamydia again
  • you had unprotected sex with a partner before the treatment for both of you was finished (see How soon can I have sex again?).
  • you didn’t complete the treatment or didn’t take it according to the instructions
  • the signs and symptoms don’t go away (see When will the signs and symptoms go away?)
  • your test was negative but you develop signs or symptoms of chlamydia (see What are the signs and symptoms?).

In these situations you may need a repeat test. This can be done 5–6 weeks after the first test.


You may need more antibiotics.


If you were treated for chlamydia in pregnancy you’ll be advised to have another test.


You can go back to the doctor, nurse or clinic if you have any questions or need advice on how to protect yourself from infection in the future.

Only some people who have chlamydia will have complications. If chlamydia is treated early, it’s unlikely to cause any long-term problems. However, without proper treatment the infection can spread to other parts of the body. The more times you have chlamydia the more likely you are to get complications.

  • In women, chlamydia can spread to other reproductive organs causing pelvic inflammatory disease (PID). This can lead to long-term pelvic pain, blocked fallopian tubes, infertility and ectopic pregnancy (when the pregnancy develops outside the uterus, usually in a fallopian tube).
  • In women, chlamydia can also cause pain and inflammation around the liver. This usually gets better with the correct antibiotic treatment.
  • In men, chlamydia can lead to infection in the testicles and possibly reduce fertility.
  • Rarely, chlamydia can lead to inflammation of the joints in both men and women. This is known as Sexually Acquired Reactive Arthritis (SARA) and it is sometimes accompanied by inflammation of the urethra (tube where urine comes out) and the eye. This is more likely to occur in men than women.

It can, but it can take a long time. If you delay seeking treatment you risk the infection causing long-term damage and you may still be able to pass the infection on to someone else.

Don’t have oral, vaginal or anal sex, or use sex toys, until seven days after you and your partner(s) have both finished the treatment and any symptoms have gone. This is to help prevent you being re-infected or passing the infection on to someone else.


If you’re given antibiotic treatment called azithromycin that you take for only one day you’ll still need to avoid sex for seven days after you have taken the tablets.


The chlamydia test can’t tell you how long the infection has been there.


If you feel upset or angry about having chlamydia and find it difficult to talk to a partner or friends, don’t be afraid to discuss how you feel with the staff at the clinic or general practice.

If the test shows that you have chlamydia then it’s very important that your current sexual partner(s) and any other recent partners are also tested and treated.


You may be given a ‘contact slip’ to send or give to your partner(s) or, with your permission, the clinic can contact your partner(s) for you. This is called partner notification. It can sometimes be done by text message. The message or contact slip will say that they may have been exposed to a sexually transmitted infection and suggest they go for a check-up. It may or may not say what the infection is. It won’t have your name on it, so your confidentiality is protected. 


You’re strongly advised to tell your partner(s), but it isn’t compulsory. The staff at the clinic or general practice can discuss with you which of your sexual partners may need to be tested.

Chlamydia is just one of many factors that can affect your fertility. Most women who’ve had chlamydia won’t become infertile or have an ectopic pregnancy (see What happens if chlamydia isn’t treated?). If you’ve had chlamydia you won’t normally be offered any routine tests to see if you’re fertile unless you or your partner are having difficulty in getting pregnant. If you’re concerned, talk to your doctor or practice nurse.

  • Chlamydia during pregnancy has been associated with problems such as premature (early) birth, and infection of the uterus (womb) lining after the birth.
  • It can be passed to the baby during the birth and (less commonly) before the baby is born. This can cause inflammation and discharge in the baby’s eye(s) (conjunctivitis) and/or pneumonia.
  • Chlamydia can be treated with antibiotics when you’re pregnant and when you’re breastfeeding. The antibiotics won’t harm the baby, but do tell the doctor or nurse that you're pregnant.
  • You may be offered a chlamydia test as part of your antenatal care.

No, chlamydia does not cause cervical cancer.

The following measures will help protect you from chlamydia and most other sexually transmitted infections, including HIV.


It’s possible to get a sexually transmitted infection (STI) by having sex with someone who has the infection but has no symptoms. You can also have an STI yourself without knowing it.


These steps will also help protect you from getting or passing on an infection without knowing it.

  • Use condoms (male or female) every time you have vaginal or anal sex.
  • If you have oral sex (going down, giving head), use a condom to cover the penis, or a latex or polyurethane (soft plastic) square to cover the female genitals or male or female anus.
  • f you’re a woman and rub your vulva against a female partner’s vulva one of you should cover the genitals with a latex or polyurethane square.
  • If you’re not sure how to use condoms correctly visit for more information.
  • Avoid sharing sex toys. If you do share them, wash them or cover them with a new condom before anyone else uses them.

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This website can only give you general information about sexually transmitted infections. The information is based on evidence-based guidance produced by The British Association for Sexual Health and HIV (BASHH) and the National Institute for Health and Care Excellence (NICE).

Remember – contact your doctor, practice nurse or a clinic if you are worried or unsure about anything.

INFORMATION LAST UPDATED DECEMBER 2016. Next planned review December 2018.