What Is Chlamydia?

Chlamydia is a sexually transmitted infection (STI) caused by the bacteria Chlamydia trachomatis. You can get the infection through vaginal, anal, and oral sex. However, the infection can sometimes go undetected because most people with chlamydia do not show symptoms at all.

Chlamydia is still transmissible (meaning, you can still pass it on to someone else), even when symptoms are not present. When symptoms do appear, they include a burning sensation when peeing, unusual discharge, and pain during sex.

Getting tested for chlamydia is the only way to know if you have an infection. Your healthcare provider will test for chlamydia by collecting a urine (pee) sample or swab fluid from the throat, vagina or cervix, rectum, or urethra.

If you receive a positive result for chlamydia, your provider will likely prescribe you an antibiotic medication to help treat symptoms. There's good news: antibiotic treatment is 95% effective in treating a chlamydia infection. But when left untreated, chlamydia infection can lead to health problems like pelvic inflammatory disease (PID). That's why knowing the symptoms and getting an early diagnosis are so important.


Most people who have chlamydia are asymptomatic, meaning that they do not show any symptoms at all. Up to 90% of women and up to 70% of men with chlamydia don't experience symptoms.

Even in cases where symptoms are not present, it is easy to transmit chlamydia without knowing you have an active infection. Even more, chlamydia infection can cause symptoms inside the body, affecting different reproductive organs.

When symptoms do appear, they can range from mild to severe. In fact, it might take several weeks after having sex with a partner who has chlamydia for symptoms to appear. If you do develop symptoms, it's common to experience:

Chlamydia infection can also spread to your rectum or anus, causing rectal pain, discharge, and bleeding. Although very uncommon, chlamydia infection can cause reactive arthritis, which can cause joint pain and inflammation in the eyes.


Chlamydia is an STI caused by the bacteria Chlamydia trachomatis. The bacteria can be transmitted through vaginal, oral, or anal sex with a person who has the infection. If a pregnant person has chlamydia, the infection can also be passed on to their baby during childbirth.

Chlamydia is very common in sexually active people between the ages of 15 and 24 years old. Due to a lack of symptoms, regular screening for chlamydia (along with other STIs) is recommended if you have an increased risk of getting chlamydia. You should get tested at least once a year for chlamydia if you:

  • Are younger than 25 years old and are sexually active
  • Have a new sexual partner or more than one sexual partner
  • Are not using a condom every time during sex
  • Have a sexual partner who has chlamydia or another STI
  • Are pregnant
  • Have HIV


Getting tested for chlamydia is the only way to know if you have an infection. This is especially true since most people with chlamydia do not typically show any symptoms.

One test healthcare providers use for chlamydia is nucleic acid amplification testing (NAAT). NAAT involves detecting or looking for the bacteria in a sample of fluid from your body. Your healthcare provider may test for chlamydia by collecting a urine (pee) sample or swab fluid from your:

  • Throat
  • Vagina or cervix
  • Rectum (part of the intestine that connects to the anus)
  • Urethra (the tube connected to the bladder that carries urine out of your body)

A urine test is another common way to find out if you have chlamydia. Results may take about 1 to 2 days to get back. Sometimes, your provider may order a blood test or antigen test to diagnose chlamydia, in the case that NAAT is not available.

Because chlamydia is transmitted through sex, it's common practice for healthcare providers to also test you for other STIs like HIV, syphilis, and gonorrhea at the same time as chlamydia testing.


If you test positive for chlamydia, your healthcare provider will prescribe antibiotics to treat and cure the infection. The goal of treatment is to:

  • Improve symptoms
  • Reduce your ability to transmit the infection to your partners
  • Prevent health complications related to the chlamydia infection

Your healthcare provider may prescribe a seven-day course of Monodox (doxycycline). If you are unable to take doxycycline or have trouble taking antibiotics for seven days, your provider may prescribe your Zithromax (azithromycin)—a one-time treatment you can take by mouth.

It's important to keep in mind that you cannot have sex while you're taking medication for chlamydia. You and your sexual partners will be asked to abstain from sex until one week after completing treatment. Your healthcare provider may have you follow up in four weeks to make sure that the infection is no longer in your system.

How to Prevent Chlamydia

As with other sexually transmitted infections, there are ways to prevent or lower your risk of chlamydia. The only way to prevent chlamydia is to abstain from vaginal, oral, or anal sex. When abstaining from sex is not possible, ways to lower your risk of chlamydia include:

  • Practicing safe sex, such as using condoms or dental dams
  • Seeing your healthcare provider as soon as possible if you have symptoms of chlamydia or another STI
  • Getting screened for STIs routinely
  • Avoiding sex with your partner if they have symptoms of chlamydia or another STI
  • Limit the number of your sexual partners

Comorbid Conditions

When left untreated, chlamydia can lead to health problems like pelvic inflammatory disease (PID). Fortunately, PID treatment is typically successful in reducing symptoms. If you develop PID and don't receive treatment, it can lead to:

  • Long-term abdominal or pelvic pain
  • Scarring of the fallopian tubes in people assigned female at birth
  • Increased risk of ectopic pregnancy (a type of pregnancy that grows and develops in the fallopian tubes rather than the uterus)
  • Infertility

Getting chlamydia while pregnant can also cause health complications like miscarriage or premature birth. If the birth parent has chlamydia, the infection can be passed on to the baby during birth. As a result, the baby can develop conjunctivitis (pink eye), which can damage the baby's eyes and affect their vision over time. Newborns with a chlamydia infection can also develop pneumonia which can cause cough and trouble breathing.

Living with Chlamydia

Chlamydia is curable when you begin treatment as soon as possible. In fact, antibiotic treatment is 95% effective in treating the infection. It’s important to finish the full round of antibiotics that your healthcare provider prescribes you, even if you start to feel better or notice that your symptoms are improving.

In most cases, your healthcare provider will ask you to come in for a follow-up visit in four weeks to see if you still have the infection. Following treatment, your provider will test for chlamydia and other STIs after three months to check for reinfection.

Reinfection is common and typically occurs when sexual partners who may have been exposed to chlamydia don't receive or complete their treatment. Research has shown that as many as 25% of people are reinfected with chlamydia by untreated sexual partners. To prevent back-and-forth reinfection, it's important for both you and your sexual partners to seek chlamydia treatment.

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8 Sources
Health.com uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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