Chlamydia is 1 of the most common sexually transmitted infections (STIs) in the UK.
It's passed on through unprotected sex (sex without a condom) and is particularly common in sexually active teenagers and young adults.
If you live in England, are under 25 and are sexually active, it's recommended that you get tested for chlamydia every year or when you change sexual partner.
Most people with chlamydia do not notice any symptoms and do not know they have it.
If you do develop symptoms, you may experience:
If you think you're at risk of having a sexually transmitted infection (STI) or have any symptoms of chlamydia, visit a GP, community contraceptive service or local genitourinary medicine (GUM) clinic to get tested.
Chlamydia is a bacterial infection. The bacteria are usually spread through sex or contact with infected genital fluids (semen or vaginal fluid).
You can get chlamydia through:
It can also be passed by a pregnant woman to her baby.
Find out more about the complications of chlamydia
Chlamydia cannot be passed on through casual contact, such as kissing and hugging, or from sharing baths, towels, swimming pools, toilet seats or cutlery.
Although chlamydia does not usually cause any symptoms and can normally be treated with a short course of antibiotics, it can be serious if it's not treated early on.
If left untreated, the infection can spread to other parts of your body and lead to long-term health problems, such as pelvic inflammatory disease (PID), epididymo-orchitis (inflammation of the testicles) and infertility.
It can also sometimes cause reactive arthritis.
This is why it's important to get tested and treated as soon as possible if you think you might have chlamydia.
Find out more about the complications of chlamydia
Testing for chlamydia is done with a urine test or a swab test.
You do not always need a physical examination by a nurse or doctor.
Anyone can get a free and confidential chlamydia test at a sexual health clinic, a genitourinary medicine (GUM) clinic or a GP surgery.
People under 25 years old can also get tested by the National Chlamydia Screening Programme (NCSP).
This is often in places such as pharmacies, contraception clinics or colleges.
If you live in England, you're under 25 and you're sexually active, you should get tested for chlamydia every year or when you change sexual partner, as you're more likely to catch it.
You can also buy chlamydia testing kits to do at home.
Find out more about getting a chlamydia test
Chlamydia can usually be treated easily with antibiotics.
You may be given some tablets to take all on 1 day, or a longer course of capsules to take for a week.
You should not have sex until you and your current sexual partner have finished treatment.
If you had the 1-day course of treatment, you should avoid having sex for a week afterwards.
It's important that your current sexual partner and any other recent sexual partners you have had are also tested and treated to help stop the spread of the infection.
Under-25s who have chlamydia should be offered another test around 3 months after being treated.
This is because young adults who test positive for chlamydia are at increased risk of catching it again.
Sexual health or genitourinary medicine (GUM) clinics can help you contact your sexual partners.
Either you or the clinic can speak to them, or they can be sent a note advising them to get tested.
The note will not have your name on it, so your confidentiality will be protected.
Anyone who's sexually active can catch chlamydia.
You're most at risk if you have a new sexual partner or do not use a barrier method of contraception, such as a condom, when having sex.
You can help to prevent the spread of chlamydia by:
If you do share sex toys, wash them or cover them with a new condom between each person who uses them.
Find answers to some common questions about chlamydia: