Chlamydia is curable with antibiotics. The CDC-preferred treatment is doxycycline 100 mg by mouth twice daily for 7 days CDC Tx Guidelines. Azithromycin as a single 1 g dose is an alternative. Abstain from sex until the course is finished and partners are treated, then retest about 3 months later to catch reinfection.
| Item | Reported cases |
|---|---|
| Chlamydia | 1,648,568 |
| Gonorrhea | 601,319 |
| Syphilis (P&S) | 53,007 |
The essentials
Chlamydia is an infection caused by the bacterium Chlamydia trachomatis; most US genital cases come from serovars D through K. It's the most commonly reported bacterial STI in the country, with roughly 1.65 million reported cases in 2023, a rate of about 492 per 100,000 that has stayed roughly flat across recent years CDC AtlasPlus, 2023. The burden isn't even across the map. Washington, DC, Louisiana, and Mississippi report rates more than double the national figure.
This is a routine, curable infection CDC. Clinics handle it every day. Testing positive is a medical event, and in many states you can notify partners anonymously so they get treated too. It spreads so widely because it's usually silent, and most infections turn up on screening rather than from a symptom that sent someone in.
Symptoms — and why most people have none
Chlamydia is a 'silent' infection. About three quarters of infected women and roughly half of infected men have no symptoms at all. The bacterium can live on the mucous membranes of the cervix, urethra, rectum, or throat without causing anything you'd notice, so it keeps circulating, and routine testing beats waiting for a sign.
In women
When symptoms do appear, women may notice abnormal vaginal discharge or a burning feeling when urinating. If the infection climbs from the cervix into the upper reproductive tract, it can cause lower-abdominal or low-back pain, fever, pain during intercourse, and bleeding between periods. These are warning signs of pelvic inflammatory disease (PID), an infection of the uterus and fallopian tubes that can scar the tubes and threaten future fertility.
In men
Men may see penile discharge that's often clear or cloudy, sometimes just a single drop noticed in the morning, along with burning on urination or burning and itching at the tip of the penis. Less commonly, the infection spreads to cause testicular pain or swelling, a sign of epididymitis (inflammation of the coiled tube behind the testicle that stores sperm), which can occasionally affect fertility if untreated.
Rectal and throat infections
Rectal infection can cause rectal pain, discharge, or bleeding, but is frequently silent. Pharyngeal (throat) infection from oral sex is typically asymptomatic; you generally won't know it's there without a swab of that site.
Testing: how to know for sure
The recommended test is a NAAT (nucleic acid amplification test), the gold standard for both genital and extragenital infection because it detects the bacterium's genetic material with high accuracy. It runs on several specimen types: a first-catch urine sample, a self- or clinician-collected vaginal swab, an endocervical or male urethral swab, and rectal or pharyngeal swabs when those exposures apply.
In practice, testing is undramatic. You'll typically pee into a cup, and holding your urine for about an hour first improves the catch, or you collect your own swab. There's no blood draw and no painful urethral probe, and results are often texted back within a few days. Free or low-cost testing is available at Planned Parenthood, health departments, and Title X clinics; at-home kits run roughly $50–150, and testing is often $0 with insurance.
One common mistake costs people accurate results: testing the morning after a hookup. A NAAT is most reliable about two weeks after exposure, so a too-early negative can be falsely reassuring. If you're trying to time it, see our guide on when to test after exposure, and read the full chlamydia testing & diagnosis walkthrough before you book. You can also get tested directly.
On who should be screened, the guidance is deliberately asymmetric. The USPSTF gives a Grade B recommendation to screen all sexually active women 24 and under, but an I-statement (insufficient evidence) for screening men, because the serious complications, PID and infertility, fall on women USPSTF.
Chlamydia treatment: antibiotics and dosage
Chlamydia is cured with a course of antibiotics. The preferred regimen is doxycycline 100 mg by mouth twice daily for 7 days. Alternatives are azithromycin 1 g orally as a single dose, or levofloxacin 500 mg orally once daily for 7 days. For full regimen details and special situations, see our chlamydia treatment page.
The 2021 guidelines moved doxycycline ahead of azithromycin, which had previously been co-equal CDC STI Guidelines, 2021. Two findings drove the change: microbiologic treatment failure in men was higher with azithromycin, and doxycycline clears rectal infection far better. In a randomized trial, doxycycline cured 100% of rectal chlamydia versus 74% with single-dose azithromycin Rectal CT RCT. Rectal infection is often silent and can quietly reseed a partner, so that gap matters.
What the doxycycline course is actually like
It's a seven-day course of pills, not a one-and-done shot. Take it with food to ease nausea, and avoid strong sun, since doxycycline can make skin burn more easily. Finish every dose even after symptoms fade. Get your partners treated to head off back-and-forth reinfection, and put the 3-month retest in your calendar before you leave the clinic.
Treatment in pregnancy
Doxycycline isn't used in pregnancy. The recommended option is azithromycin 1 g orally as a single dose, with amoxicillin 500 mg three times daily for 7 days as an alternative. Pregnant patients also need a test-of-cure about four weeks after finishing treatment and a repeat test at three months, which is closer follow-up than non-pregnant patients get.
Partners, abstinence, and reinfection
Sexual partners from the prior 60 days should be referred, tested, and presumptively treated. Abstain from sex for 7 days after single-dose therapy, or until the full 7-day course is complete, whichever applies. Expedited partner therapy (EPT), where you carry medication or a prescription to your partner, is permissible in most US states but not all, so check your local rules. A landmark trial found EPT cut persistent or repeat infection, with the largest effect for gonorrhea (3% vs 11%) Golden NEJM.
Retest everyone about 3 months after treatment. This isn't a test-of-cure; it catches reinfection, which is common because partners often go untreated. A formal test-of-cure isn't advised for non-pregnant people unless adherence is in doubt, symptoms persist, or reinfection is suspected.
Lymphogranuloma venereum (LGV)
LGV is an invasive form caused by C. trachomatis serovars L1, L2, and L3, with the highest burden among men who have sex with men. It usually shows up as proctocolitis: mucoid or bloody rectal discharge, anal pain, and tenesmus (a constant urge to pass stool). Because it invades deeper tissue, it needs a longer course: doxycycline 100 mg twice daily for 21 days, with azithromycin 1 g weekly for three weeks or erythromycin base 500 mg four times daily for 21 days as alternatives CDC LGV. Partners within 60 days get presumptive doxycycline 100 mg twice daily for 7 days.
Treatment options at a glance
| Situation | Regimen | Notes |
|---|---|---|
| Preferred (non-pregnant) | Doxycycline 100 mg twice daily, 7 days | Best for rectal infection; finish full course |
| Alternative | Azithromycin 1 g single dose | One dose; lower cure for rectal/male infection |
| Alternative | Levofloxacin 500 mg once daily, 7 days | Reserve option |
| Pregnancy | Azithromycin 1 g single dose | Amoxicillin 500 mg 3×/day, 7 days as alternative; test-of-cure needed |
| LGV | Doxycycline 100 mg twice daily, 21 days | Longer course for invasive disease |
Prevention
Condoms used correctly every time reduce transmission, and a long-term mutually monogamous relationship with a tested partner is low-risk. But because most infections are silent, the steps that actually move the needle are routine screening and getting partners treated.
DoxyPEP is a newer prevention tool: a single 200 mg dose of doxycycline taken within 72 hours of sex, which reduces chlamydia by more than 70% CDC DoxyPEP, 2024. It's offered to men who have sex with men and transgender women who've had a bacterial STI in the past 12 months. It's not for everyone, so talk it through with a clinician CDC DoxyPEP.
Chlamydia and gonorrhea travel together and present similarly, so testing and treatment decisions often cover both. Our gonorrhea vs chlamydia comparison breaks down the differences.
When to see a clinician
See a clinician if you have discharge, burning on urination, pelvic or testicular pain, rectal symptoms, or bleeding between periods. Don't wait for symptoms if you've had a new or untreated partner. Seek prompt care for fever with lower-abdominal pain, which can signal PID, and tell your provider about all sites of exposure so the right swabs are taken. If you've been treated, return for the 3-month retest even if you feel completely fine.