What is chlamydia?

Chlamydia is a common sexually transmitted infection (STI) that’s caused by a bacteria called chlamydia trachomatis (C. trachomatis). Once a person's infected, they can spread chlamydia to their partners through intercourse, anal sex or oral sex. Infections can also occur when partners share sex toys that have become contaminated with the bacteria responsible for chlamydia.

Chlamydia infections are treatable and curable. But it’s important to receive treatment as soon as possible. Left untreated, chlamydia can lead to serious complications.

Who does chlamydia affect?

Anyone who’s sexually active can get chlamydia. The bacteria that causes chlamydia gets transmitted through vaginal fluid and semen, which means that people of all genders who have sex can become infected with chlamydia and infect their partners, too. If you’re pregnant and have chlamydia, you can pass it on to your newborn.

How common is chlamydia?

Chlamydia is the most common STI caused by bacteria. Nearly 2 million cases of chlamydia were reported to the CDC in 2019. The number of infections is likely even higher. When compared to previous years, 2019 infection rates increased among people of all genders, all races and ethnicities, and in every region of the U.S. Most cases of chlamydia are asymptomatic, which means there are no signs or symptoms of an infection. Many of these cases likely go unreported.

Certain demographic characteristics (like age, gender and race) may make you more likely to get diagnosed with chlamydia. You’re more likely to get diagnosed if you’re:

  • A teen or young adult aged 15 to 24. More than half of all diagnosed chlamydia cases in the U.S. occur in this age group.
  • A cisgender woman aged 15 to 24. Young women in this age group are targeted for chlamydia screenings, and the rate of infection among those who are tested is high.
  • A man who has sex with men (MSM). Chlamydia infections disproportionately affect men who have sex with men.
  • Black and non-Hispanic. Chlamydia infections disproportionately affect non-Hispanic Black populations.

Higher rates of transmission among certain groups are less about sexual behavior and more about networks and lack of access to STI prevention resources. For example, chlamydia is more likely to spread from person to person within communities that have higher infection rates. And it’s more likely to spread among groups that don’t have easy access to sex education or barriers to STIs like condoms and dental dams.

Symptoms and Causes

What causes chlamydia?

Chlamydia infections spread through sexual contact, when vaginal fluid or semen containing the bacteria that causes chlamydia travels from one person to another. Sexual contact includes all kinds of sex, including sex that doesn’t involve penetration or ejaculation. There are lots of ways that the fluids from one person’s genitals can transmit the bacteria that causes chlamydia.

  • Intercourse. Bacteria pass from one person’s penis to their partner’s vagina or vice versa.
  • Anal sex. Bacteria passes from one person’s penis to their partner’s anus or vice versa.
  • Oral sex. Bacteria passes from one person’s mouth to their partner’s penis, vagina, or anus, or vice versa.
  • Sex involving toys. Bacteria pass from a toy with the bacteria to a person’s mouth, penis, vagina or anus.
  • Manual stimulation of the genitals or anus. Less commonly, infected vaginal fluid or semen can come in contact with a person’s eye, causing an infection called conjunctivitis. For example, this can happen if you touch the genitals of an infected person and then rub your eyes without washing your hands first.

What doesn’t cause chlamydia?

Not all situations involving an exchange of body fluids or intimacy cause chlamydia. You can’t get chlamydia from:

  • Kissing.
  • Sharing food or drinks.
  • Hugging or holding hands.
  • Using a toilet after someone else.
  • Inhaling droplets after someone coughs or sneezes.

How long can you have Chlamydia without knowing?

Chlamydia is sometimes called a silent infection because the majority of people who have chlamydia — regardless of gender — never notice symptoms. People who do notice symptoms often don’t recognize the signs that they have chlamydia until a few weeks after they’ve been infected. Because chlamydia cases are often asymptomatic, it’s easy to spread chlamydia to someone else without realizing it. And it’s easy to miss out on receiving the treatment needed to prevent the serious complications that can result from chlamydia.

What are the symptoms of Chlamydia?

If you do notice symptoms, you’ll likely experience them differently based on your reproductive anatomy. Many of the symptoms that cisgender women experience can also affect transgender men and nonbinary individuals with vaginas. Many of the symptoms that cisgender men notice can affect transgender women and nonbinary individuals with penises, too.

Signs of chlamydia if you have a vagina

Chlamydia bacteria often cause symptoms that are similar to cervicitis or a urinary tract infection (UTI). You may notice:

  • White, yellow or gray discharge from your vagina that may be smelly.
  • Pus in your urine (pyuria).
  • Increased need to pee.
  • Pain or a burning sensation when you pee (dysuria).
  • Bleeding in between periods.
  • Painful periods.
  • Painful intercourse (dyspareunia).
  • Itching or burning in and around your vagina.
  • Dull pain in the lower part of your abdomen.

Signs of chlamydia if you have a penis

Chlamydia bacteria most often infect your urethra, causing symptoms that are similar to nongonococcal urethritis. You may notice:

  • Mucus-like or clear, watery discharge from your penis.
  • Pain or a burning sensation when you pee (dysuria).

Signs of chlamydia that all genders may notice

Chlamydia can affect parts of your body other than your reproductive organs, such as your:

  • Anus. You may notice pain, discomfort, bleeding or a mucus-like discharge from your bottom.
  • Throat. You may have a sore throat, but you usually won’t notice symptoms if the bacteria’s in your throat.
  • Eyes. You may notice symptoms of conjunctivitis if C. trachomatis bacteria gets in your eye. Symptoms include redness, pain and discharge.

See your healthcare provider immediately if you notice any of these symptoms.

Diagnosis and Tests

How is Chlamydia diagnosed?

The most common test for chlamydia is called a nucleic acid amplification test (NAAT). Your provider takes a sample of fluid by doing a vaginal/cervical swab or collecting a urine sample. Then, they send the sample off to a lab to check for the bacteria that causes chlamydia. Your provider may do the test in an office, or they may ask you to do an at-home chlamydia test. Follow your provider’s instructions carefully to ensure you get accurate test results.

Because most chlamydia cases are asymptomatic, it’s important to get screened for chlamydia even if you don’t notice any signs of infection. The CDC recommends that sexually active cisgender women who are high-risk for chlamydia get screened regularly. Women, more so than men, experience the most severe complications from chlamydia. Transgender men and nonbinary individuals with vaginas should be screened regularly, too, as they can experience the same complications of chlamydia.

You’re considered high-risk if you:

  • Are under 25.
  • Are pregnant.
  • Have a new partner.
  • Have multiple partners.
  • Have had chlamydia infections previously.

Cisgender men, or trans and nonbinary individuals with penises, should be screened for chlamydia if:

  • They live in a setting where chlamydia spreads frequently, like correctional facilities, adolescent clinics and sexual health clinics.
  • They have sex with other men.

Regardless of your age, reproductive anatomy, or other risk factors — you should discuss your sexual history and sexual activity with your healthcare provider. Your provider is your best resource for offering guidance on how often you should be tested for chlamydia and other STIs.

Management and Treatment

How is chlamydia treated?

Chlamydia can be cleared up with antibiotics in about a week or two. But don’t stop taking your medication just because your symptoms improve. Ask your provider about what follow-up is needed to be sure your infection is gone after you’ve finished taking your medicine.

Part of your treatment should also include avoiding sexual activities that could cause you to get re-infected and ensuring that any sexual partners who may be infected also get treatment. You should:

  • Abstain from sex until your infection has cleared up. Starting treatment doesn’t mean that you’re in the clear. Take all your medication as your provider directs, and avoid all sexual contact in the meantime.
  • Contact all sexual partners. Tell any sexual partners from the last 3 months that you’re infected so that they can get tested, too.
  • Get tested for other STIs (HIV/AIDS, syphilis, herpes, gonorrhea). It’s common to have multiple STIs, and it’s important to receive treatment that’s tailored to each infection.

Antibiotics can get rid of your infection, but they can’t reverse any harm the bacteria may have caused to your body before treatment. This is why it’s so important to get screened regularly for chlamydia, to see your provider at the first sign of symptoms, and get treatment immediately if you’re infected.

What medications are used to get rid of chlamydia?

The most common antibiotics used to treat chlamydia infections are:

  • Azithromycin. Usually taken as a single dose.
  • Doxycycline. Usually taken over 7 days.

Make sure you only take antibiotics prescribed by your provider, and take all medications until they’re gone, even if your symptoms improve.

Can chlamydia be cured?

Yes. Chlamydia can be treated and cured. Some sexually transmitted bacterial infections are starting to become resistant to antibiotics, though, and this makes them harder to treat. With this in mind, the best way to fight chlamydia is to prevent infections from spreading.

What can happen if chlamydia isn’t treated?

Untreated chlamydia can put your health at risk. Make an appointment with your provider immediately if you notice any symptoms of chlamydia, and get regular STI screenings to avoid complications later.

Complications of chlamydia for people with vaginas

Untreated chlamydia can cause:

  • Pelvic inflammatory disease (PID). PID is a serious condition that requires hospitalization. It can occur when an untreated STI, like chlamydia, damages your reproductive organs. PID can lead to infertility and chronic pelvic pain. It can also cause an ectopic pregnancy, which is life-threatening for the fetus and potentially deadly for the mother or gestational parent, too.
  • Pregnancy complications. An untreated infection can lead to pre-term delivery. Also, if you’re pregnant and have chlamydia, you can pass the infection on to your newborn. Babies born with chlamydia may have pneumonia or conjunctivitis that could lead to blindness if not treated.

Complications of chlamydia for people with penises

Untreated chlamydia can cause:

  • Epididymitis. Infection can spread to the testicles and the tube that carries sperm to your testicles (epididymis), causing symptoms like pain, swelling and tenderness in your testicles.
  • Reduced fertility. Chlamydia can harm your sperm, negatively impacting your ability to conceive.

Complications of chlamydia that can affect all genders

Untreated chlamydia can:

  • Increase your risk of getting reactive arthritis, which causes your joints to swell and feel painful.
  • Increase your chances of contracting HIV.

How soon after treatment will I feel better?

You should start to feel better within a week after you begin taking antibiotics. Be sure to continue taking your antibiotics until they’re gone, even if your symptoms improve.

Care at Cleveland Clinic


How can I protect myself from chlamydia?

The only way to avoid getting chlamydia is to abstain from having vaginal, anal or oral sex with someone who has a chlamydia infection. And be sure that sex toys that carry the bacteria don’t come in contact with your genitals.

It’s not always possible to know if a current or potential partner has chlamydia, though, especially since many people with chlamydia never notice symptoms. With prevention in mind, it’s a good idea to make safer sex practices a regular part of your sex life:

  • Use condoms during intercourse, anal sex and oral sex.
  • Use dental dams during oral sex or vagina-to-vagina contact.
  • Don’t share sex toys, but if you do, wash them after each use and cover toys used for penetration with a condom.
  • Have sex with only one partner, who only has sex with you.

Outlook / Prognosis

How long does chlamydia last?

With treatment, chlamydia should go away within a week or two. It’s important to take all antibiotics to fight the infection. Don’t have sex during treatment, or you could get reinfected.

Does chlamydia go away on its own?

You should never wait for chlamydia to go away on its own. Left untreated, chlamydia can cause serious harm to your health. If you are sexually active, you run the risk of infecting others, putting them at risk of experiencing severe complications as well.

Living With

When should I see my healthcare provider?

When it comes to chlamydia, it’s a good idea to be proactive. Speak with your healthcare provider about your risks of infection. Make a plan to get screened regularly for STIs based on your provider’s recommendations for how often you should be tested. Make an appointment with your healthcare provider if your partner tests positive for chlamydia or if you notice any signs or symptoms that you may be infected.

Frequently Asked Questions

What are the first symptoms of chlamydia?

Most people who have chlamydia never notice symptoms. But an unusual discharge from your vagina or penis may be a sign that you have a chlamydia infection. Pain, bleeding or a discharge from your bottom can also be a sign of chlamydia.

Does chlamydia have a smell?

Chlamydia doesn’t always have a smell. But one of the symptoms of chlamydia is an unusual vaginal discharge that has an unpleasant odor.

How did I get chlamydia if I didn’t cheat?

You can get chlamydia if your partner had vaginal, oral or anal sex with someone who was infected and then had sex with you. People in relationships may have different ideas about what kinds of sexual contact counts as “cheating,” and this miscommunication can lead to infections. Communicate honestly with your partner about what sex you’re having and what sex they’re having. Practice safer sex to reduce your risk of catching chlamydia, and get regularly screened to be sure.

A note from Cleveland Clinic

It can be embarrassing to talk about anything sex-related with your healthcare provider, including STI prevention. But your sex life is an important part of your health that your provider needs to know about to care for you. Not getting the treatment you need for chlamydia can pose serious risks to your health. Speak with your provider about getting regularly screened for chlamydia and other STIs to reduce your risks of complications. Practice safer sex to prevent the spread of chlamydia.

Last reviewed by a Cleveland Clinic medical professional on 11/01/2021.


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  • Geisler WM, Lensing SY, Press CG, Hook EW 3rd. Spontaneous resolution of genital Chlamydia trachomatis infection in women and protection from reinfection. ( J Infect Dis. 2013;207(12):1850-1856. Accessed 11/9/2021.
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