What it means
Chlamydia is a bacterium, Chlamydia trachomatis. It infects the genitals, rectum, throat or eyes depending on the contact involved, and it spreads through vaginal, anal or oral sex, and through sharing sex toys.
It is one of the most common infections in the world. Because it so often causes no symptoms, most people who have it do not know.
What can vary
Most people have no symptoms at all. When symptoms do appear, they typically start 1-3 weeks after infection.
If symptoms appear, they may include unusual discharge from the vagina, penis or rectum; pain or burning when urinating; pain in the lower abdomen or testicles; sore throat or earache from throat infection; or redness and discharge in the eye.
Symptoms can come and go. A symptom-free stretch does not mean the infection has cleared.
Possible explanations
Chlamydia is confirmed by testing, not by symptoms. A urine sample or a swab can detect it, and self-collected vaginal and rectal swabs are commonly available and usually more comfortable.
A positive result is treated with a short course of antibiotics, with advice to avoid sex until treatment is finished. Partners should be tested and treated too, which is why clinics often offer partner notification.
Warning signs
- Pain in the testicles or lower abdomen, with or without discharge. This suggests the infection may have spread upward. Untreated infection can cause lasting pelvic pain and fertility problems.
- Fever with pelvic pain — same-day assessment needed.
- Eye redness or discharge — prompt care rather than self-treatment.
Untreated chlamydia does not usually cause immediate dramatic harm. That is exactly what makes testing worth doing.
What to do next
If you have had unprotected sex and could have been exposed, get tested. Testing is straightforward and there is no reason to worry in the meantime.
If you have symptoms, book an appointment with a sexual health service or your GP. Many services offer self-testing kits.
Self-care
There is no self-care that cures chlamydia, and that is worth stating plainly. Home remedies delay the only treatment that works.
What you can do: get tested, complete the full antibiotic course, avoid sex until you have finished, and make sure partners are treated.
When to seek help
Routine: testing after unprotected sex, or with a new partner.
Prompt: symptoms, or if you are pregnant.
Emergency: fever with pelvic or testicular pain.
How to talk about it
“I had unprotected sex and I want to get tested.”
“I’ve noticed a discharge and I’m not sure what it is.”
“My partner tested positive and I’ve been exposed.”
Sexual health services see this constantly. Saying “I think I might have an STI” is a perfectly serviceable opening sentence.
Myths and stigma
“You get chlamydia from being careless.” Chlamydia is among the most common infections in the world, and most people who have it had no symptoms and no idea. It is not a moral judgement, and a diagnosis does not say anything about someone’s choices or relationships.
“Only certain kinds of people get it.” Anyone who is sexually active can get it. The people most likely to be diagnosed are simply the ones most likely to be tested, which usually reflects access to healthcare rather than behaviour.
“If you get treated, you will be fine forever.” Treatment is usually straightforward, but reinfection is common if a partner is not treated too. That is why partner treatment is offered.
Prevention
- Condoms reduce transmission substantially, though they do not eliminate it, because infection can occur on skin a condom does not cover.
- Regular testing is the single most effective thing, because most chlamydia is silent. Testing after a new partner, and routinely if you have multiple partners, catches it before it is passed on.
- Partner treatment matters. If a partner is not treated, reinfection is common.
- No vaccine exists.
Related articles
Sources
Public sources are linked so you can read the detail rather than take this site’s word for it. None of this has yet been reviewed by a qualified clinician — see how we handle medical review.
References
Where this comes from
Linked so you can check it against a recognised public health source rather than take this site's word for it.
- Sexually transmitted infections — CDC US Centers for Disease Control and Prevention (opens in a new tab)
- Chlamydia — NHS NHS (opens in a new tab)
These are public sources from recognised health organisations, linked so you can read the detail rather than take this site's word for it. Reading them does not tell you whether any of it applies to you, and none of these articles has yet been reviewed by a qualified clinician. How we handle sourcing and review.