No — non-gonococcal urethritis (NGU) isn't always from sex. Most cases trace to a sexually transmitted organism, but NGU is a syndrome rather than a single infection: in roughly half of cases no organism is found at all, and some are linked to viruses or irritants rather than a partner. The label simply means urethral inflammation that isn't gonorrhea.
with the right treatment
testing, not symptoms, decides
| Item | Value |
|---|---|
| Curable? | yes — with the right treatment |
| Tested by | NAAT / lab |
| Often | no symptoms |
| If you may have it | get tested — testing, not symptoms, decides |
What NGU actually is
NGU describes inflammation of the urethra — the tube that carries urine (and, in men, semen) out of the body — when gonorrhea has been ruled out. It's a diagnosis of pattern rather than a named bug. Several different organisms can produce the same picture: Chlamydia trachomatis, Mycoplasma genitalium, and sometimes Trichomonas, herpes simplex virus (HSV), or adenovirus CDC, 2021. About half of NGU cases never have a specific organism identified, even after good testing. For a fuller breakdown of every trigger, see our page on ngu causes.
So when someone asks whether NGU "counts" as an STI: usually the underlying cause is sexually transmitted, but not always. Adenovirus, for instance, is a respiratory and eye virus that can occasionally inflame the urethra. HSV can do the same. A meaningful share of cases have no identifiable infection, meaning physical irritation, a non-infectious process, or a pathogen below the limit of current tests may be at play. NGU describes what the urethra is doing. It doesn't prove how it got there.
Symptoms — and the silent reality
When NGU does cause symptoms, the classic trio is urethral discharge that's mucoid (cloudy, thin) or purulent (thicker, yellow-green), pain or burning when you pee, and itching or irritation inside the urethra. It presents mainly in men, where the discharge and discomfort are hard to ignore. But some of the infections behind NGU cause no symptoms at all. Chlamydia in particular is often silent, so people pass it on without knowing, and routine screening matters more than waiting for a sign.
Because symptoms can be absent, you can't rule NGU in or out by how you feel. A clear sample under a microscope or a urine test tells you what's happening even when you feel fine.
How NGU spreads
The sexually transmitted causes — chlamydia, M. genitalium, trichomonas, HSV — pass through vaginal, anal, or oral sex when mucous membranes and genital fluids make contact. That's the usual route, and it's why partner treatment is part of the plan. But the non-sexual angle is real: adenovirus can reach the urethra through routes that aren't sexual, HSV can recur without new exposure, and the large "no organism found" group isn't explained by transmission at all. NGU is most often acquired through sex, but a diagnosis is not automatic proof of a partner's infidelity or of any single exposure.
How NGU is tested
NGU isn't diagnosed on symptoms alone. A clinician needs objective evidence that the urethra is actually inflamed. That means one of the following: a Gram stain of urethral secretions showing at least two white blood cells per oil-immersion field with no gonococci present, or a positive leukocyte esterase test or at least ten white blood cells per high-power field on a first-void (first-catch) urine sample. On top of confirming inflammation, the lab runs a NAAT (nucleic acid amplification test) for chlamydia and gonorrhea, and — in persistent or recurrent cases — for M. genitalium.
In practice, this is far less involved than it sounds. Most of it comes from a simple sample: a urine cup, a self-collected swab, or a brief exam, with results usually back in a few days. You can get this free or low-cost at health departments, Planned Parenthood, and Title X clinics. If you're timing things after a possible exposure, read up on when to test after exposure so you don't test too early and get false reassurance. When you're ready to get tested, you can also compare testing providers to find an option that fits your budget and privacy needs.
How NGU is treated
The recommended treatment is doxycycline 100 mg by mouth twice daily for seven days. It's chosen over a single dose of azithromycin because it produces better outcomes and contributes less to antibiotic resistance, especially for M. genitalium. The alternative regimen is azithromycin 1 g as a single dose. For persistent or recurrent NGU, the clinician should re-confirm that urethritis is still present and test for M. genitalium; if that's positive, the approach is doxycycline followed by moxifloxacin 400 mg daily for seven days.
Treatment is a defined course. Finish every dose even after the discharge and burning fade, because stopping early invites the infection and resistance back. Ask your clinician whether your partner needs treating too, since untreated partners are the main reason NGU bounces back and forth. For the full regimen detail and how to handle a course that doesn't work, see our guide to ngu treatment. And if you're wondering whether you can skip antibiotics entirely, read whether can ngu go away on its own without treatment? before you decide to wait it out.
Complications if NGU is left untreated
Ignoring NGU can let the underlying infection climb and spread. In men, that can mean epididymitis (inflammation of the coiled tube behind the testicle, which causes pain and swelling and can threaten fertility), prostatitis (inflammation of the prostate gland, which can cause pelvic pain and urinary trouble), and reactive arthritis (joint inflammation triggered by the infection, sometimes with eye and skin involvement).
The bigger reason to treat promptly may be your partners. If the cause is chlamydia, an untreated partner can go on to develop pelvic inflammatory disease (PID) — infection that spreads to the uterus, fallopian tubes, and ovaries — which can lead to chronic pelvic pain, ectopic pregnancy, and infertility. Treating the index case alone isn't enough; the partner has to be addressed too.
How to prevent NGU
For the sexually transmitted causes, the basics still work best. Use the practical playbook below:
- Use condoms every time — they lower the risk for the sexually transmitted causes of NGU when used consistently.
- Get routine STI testing, since chlamydia and other causes are often silent and screening is the only way to catch them.
- Refer all sex partners from the prior 60 days for evaluation, testing, and presumptive treatment effective against chlamydia.
- Finish your full course of antibiotics and have your partner treated before you resume sex, so you don't reinfect each other.
NGU at a glance
| Question | Short answer |
|---|---|
| Is it always from sex? | No — usually sexually transmitted, but about half of cases have no organism found, and some causes (adenovirus, HSV) aren't always sexual. |
| How is it confirmed? | Objective evidence of urethritis (Gram stain or first-void urine) plus NAAT for chlamydia, gonorrhea, and (if persistent) M. genitalium. |
| First-line treatment | Doxycycline 100 mg twice daily for 7 days; azithromycin 1 g single dose is the alternative. |
| Do partners need treating? | Yes — partners from the prior 60 days, with treatment effective against chlamydia. |
When to see a clinician
See a clinician if you have urethral discharge, burning when you pee, or urethral itching — or if a partner tells you they've been diagnosed with an STI, even if you feel fine. NGU is common and treatable, and clinics handle it daily. The sooner it's confirmed, the sooner you and your partners are clear of it.