What Is Chlamydia?

Chlamydia is a common sexually transmitted infection (STI) caused by the bacterium Chlamydia trachomatis. It can infect the genitals, rectum, throat, and even the eyes. Chlamydia is spread through vaginal, anal, or oral sex — even if ejaculation doesn’t happen. Most people with chlamydia don’t know they have it because they often don’t experience any symptoms.

How common is chlamydia?

Chlamydia is actually the most frequently reported STI in the United States. According to the CDC, there were more than 1.6 million reported cases in 2021. But because many people never get tested, the actual number is probably much higher. It’s especially common in people ages 15 to 24, but anyone who is sexually active can get it.

What Are Symptoms of Chlamydia?

Chlamydia is often called a “silent” infection because most people don’t notice anything wrong. In fact, around 70% of people with female reproductive anatomy and 50% of those with male reproductive anatomy don’t have symptoms at all. But when symptoms do show up, they can vary based on where the infection is in the body.

In people with female biology:

Chlamydia can cause unusual vaginal discharge, a burning sensation when peeing, or pain during sex. Some may notice bleeding between periods or after sex. Others might have lower abdominal or pelvic pain that feels a bit like cramps.

In people with male biology:

Chlamydia may cause discharge from the penis — often white, yellow, or clear — or a burning sensation when urinating. Pain or swelling in one or both testicles can happen, as well as itching or irritation inside the penis.

In anyone:

Chlamydia can also infect the rectum, especially through anal sex. This can lead to pain, discharge, or bleeding. Oral sex can spread the bacteria to the throat, causing soreness. If fluids carrying the bacteria get into the eyes, it can lead to redness, itching, or discharge.

How quickly does chlamydia show up?

Chlamydia symptoms can show up as soon as 1 to 3 weeks after exposure, but many people never have symptoms at all. That’s why it’s often called a “silent” infection. Even without symptoms, chlamydia can still be passed to partners and cause long-term health issues if untreated.

How long can you have chlamydia without knowing?

It’s possible to have chlamydia for weeks, months, or even years without realizing it. That’s why regular screening is important — especially if you’ve had new sexual partners.

How can I tell if someone has chlamydia?

You can’t. Chlamydia doesn’t usually show on the outside. Someone can look perfectly healthy and still have it — or pass it on to someone else.

What Does Chlamydia Look Like?

You can’t see the bacteria itself, but you might notice signs of infection. Chlamydia can cause discharge from the penis or vagina that’s clear, white, or yellow. If it infects the eyes, you might see redness and pus-like discharge. Rectal infections may cause bleeding or discharge as well.

That said, chlamydia usually doesn’t cause sores, blisters, or rashes. If you see those, another STI might be the cause — like herpes or syphilis.

How Is Chlamydia Transmitted?

Chlamydia spreads through sexual fluids during vaginal, anal, or oral sex. It doesn’t require ejaculation — contact with fluids is enough. It can also be passed through shared sex toys if they aren’t cleaned properly or used with a new condom.

Although it’s rare, pregnant people can pass chlamydia to their babies during childbirth, which can lead to eye or lung infections in the newborn.

Who gets chlamydia?

Anyone who is sexually active can get chlamydia. It’s especially common among teens and young adults, people who have multiple partners, men who have sex with men, and those who don’t use condoms consistently.

Is sex safe with chlamydia?

It’s best to avoid sexual contact until you and your partner have both completed treatment. Even with condoms, there’s still a risk of spreading the infection through fluids or skin contact.

Can you get chlamydia from oral sex?

Yes. Giving or receiving oral sex with someone who has chlamydia can spread the infection to the throat or genitals.

Where in the body can you get chlamydia?

Chlamydia most commonly affects the cervix, urethra, rectum, throat, and eyes. The site of infection usually depends on what kind of sexual contact occurred.

How to avoid getting or spreading chlamydia:

Using condoms or dental dams every time you have sex helps reduce your risk. So does regular testing, especially with new partners. Avoid sharing sex toys unless they’re washed and covered with a new condom. Open, honest conversations with partners about STI status are one of the best ways to stay safe.

Things that help: getting tested, finishing your antibiotics, and letting your partners know.
Things that don’t help: having sex before your treatment is done, assuming no symptoms means no STI, or skipping condoms.

How Do You Test for Chlamydia?

Getting tested for chlamydia is simple and usually painless. Most tests involve a urine sample or a quick swab of the potentially infected area — such as the cervix, urethra, throat, or rectum. These samples are then sent to a lab for analysis using a highly accurate method called a NAAT (nucleic acid amplification test).

You can get tested at a doctor’s office, health clinic, or even with a reliable at-home kit.

Who should get tested?

The CDC recommends routine screening for:

• Sexually active people with female anatomy under age 25
• People 25 and older with new or multiple partners
• Pregnant individuals
• People with male anatomy who have sex with other people with male anatomy
• Anyone who has symptoms or a partner who tested positive

Do I need to get tested if I don’t have symptoms?

Yes. Most people with chlamydia don’t have symptoms, so regular testing is key to staying healthy and protecting your partners.

How soon after sex should I get tested?

If you think you’ve been exposed, wait at least 5–7 days before testing to reduce the chance of a false negative. If you test positive, plan to retest again in 3 months to check for reinfection.

Are at-home tests accurate?

Yes — when used correctly. At-home chlamydia tests are over 95% accurate and use the same NAAT technology as labs. Many services also provide prescription treatment if you test positive.

How Is Chlamydia Treated?

Chlamydia is completely curable with a short course of antibiotics. The most common treatment is doxycycline, taken twice a day for seven days. In some cases — such as pregnancy or allergies — a single dose of azithromycin may be used instead.

It’s important to finish all the medication, even if symptoms go away early. And you should avoid sexual contact for at least 7 days after starting treatment.

If your partner is also infected, they need treatment too. Otherwise, you could pass the infection back and forth.

How long does it take to fully clear?

Most people feel better within a few days, but the infection takes a full 7 days to clear after starting antibiotics.

Will I still test positive after treatment?

Possibly. Some people may still test positive for up to 3 weeks after completing treatment — even though the infection is gone. That’s why retesting right away is not recommended. Instead, wait and get tested again at 3 months.

Complications of Chlamydia

Will chlamydia go away on its own?

No. Without treatment, chlamydia can stay in your body for months or even years and cause serious health problems — even if you never have symptoms.

What happens if chlamydia isn’t treated?

In people with female anatomy, untreated chlamydia can lead to pelvic inflammatory disease (PID), which may cause chronic pelvic pain, infertility, or life-threatening ectopic pregnancy. In people with male anatomy, it can lead to painful inflammation in the testicles (epididymitis) and possible fertility issues. It can also increase your risk of getting or spreading HIV.

Can chlamydia affect pregnancy?

Yes. Chlamydia during pregnancy can lead to premature delivery, low birth weight, or infections in the baby’s eyes and lungs. That’s why STI screening is an important part of prenatal care.

Outlook & Prognosis

Can I get chlamydia again?

Yes. Even after successful treatment, you can be reinfected if you’re exposed again. Chlamydia doesn’t provide immunity, which is why testing and partner treatment are so important.

Does chlamydia ever go away on its own?

Not reliably. While some people may think they’ve cleared it because symptoms fade, the bacteria can continue to live in the body and silently cause harm. Only antibiotics can fully cure the infection.

Living With Chlamydia

If you’ve been diagnosed with chlamydia, try not to panic. It’s one of the most common STIs in the world, and it’s treatable with a single round of antibiotics. You’re doing the right thing by getting tested and taking care of yourself.

You don’t have to go through this alone. Many people feel nervous, embarrassed, or even ashamed — but those feelings are based on stigma, not facts. STIs are a normal part of being sexually active, and managing them is part of being a responsible partner.

Once you’re treated, focus on your health going forward: finish your medication, avoid sex for a week, get tested again in a few months, and talk to your partner(s) so they can take care of their health too.

How to Tell Your Partner(s) You Have Chlamydia

Telling a partner you have an STI might feel uncomfortable, but it’s an essential part of taking care of your health — and theirs.

You might say something like:

“Hey, I found out I have chlamydia. It’s really common and easy to treat, but I wanted to let you know so you can get tested too.”

Here are a few key things to remember and highlight when talking to a partner:

• Chlamydia is very common. You’re not alone — this is the most reported STI in the U.S.
• It’s curable. One short course of antibiotics is usually all it takes.
• It often has no symptoms. Many people who have it don’t know, so getting tested is the only way to be sure.
• You’re being responsible. Telling a partner helps them protect their health and prevents you from passing it back and forth.

Try to stay calm, be direct, and offer resources if you can. If a face-to-face conversation feels too hard, you can use anonymous partner notification tools or services like Chekd.

Last reviewed: May 2025

Written and medically reviewed by the Chekd Health Science Team

This content was created by Chekd Health’s Science Team, which includes experienced healthcare technologists and scientists. Our articles are based on current clinical guidelines from sources like the CDC, WHO, and peer-reviewed medical research. Each page is reviewed regularly to ensure accuracy, clarity, and up-to-date sexual health information.

This content is regularly reviewed and updated to reflect the latest medical guidelines.