Most people who have chlamydia don't notice any symptoms.
If you do get symptoms, these usually appear between 1 and 3 weeks after having unprotected sex with an infected person. For some people they don't develop until many months later.
Sometimes the symptoms can disappear after a few days. Even if the symptoms disappear you may still have the infection and be able to pass it on.
At least 70% of women with chlamydia don't notice any symptoms. If they do get symptoms, the most common include:
If chlamydia is left untreated, it can spread to the womb and cause a serious condition called pelvic inflammatory disease (PID). This is a major cause of ectopic pregnancy and infertility in women.
Read more about the complications of chlamydia.
At least half of all men with chlamydia don't notice any symptoms. If they do get symptoms, the most common include:
If chlamydia is left untreated, the infection can cause swelling in the epididymis (the tubes that carry sperm from the testicles) and the testicles. This could affect your fertility.
Read more about the complications of chlamydia.
Chlamydia can also infect:
If you have any symptoms of chlamydia, visit your GP, community contraceptive service or local genitourinary medicine (GUM) clinic as soon as possible.
You should also get tested if you don't have any symptoms but are concerned you could have a sexually transmitted infection (STI).
If you're a woman, sexually active and under 25 in England, it's recommended that you have a chlamydia test once a year, and when you have sex with new or casual partners.
If you're a man, sexually active and under 25 in England, it's recommended that you have a chlamydia test once a year if you are not using condoms with new or casual partners.
Read more about chlamydia diagnosis.