Trichomoniasis treatment is a short course of prescription antiparasitic pills. Women are now treated with metronidazole 500 mg twice daily for seven days, while men take a single 2 g dose; tinidazole 2 g as a single dose is an alternative for either CDC, 2021. Treat all partners at the same time and skip alcohol during treatment.
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 |
The essentials
Trichomoniasis is caused by Trichomonas vaginalis, a single-celled protozoan parasite that lives in the lower genital tract. It's the most common curable STI, and the most common curable non-viral STI in the US, with an estimated 2.6 million infections Sex Transm Dis, 2018. The burden falls heavily on women, who make up over 80% of cases.
The parasite spreads through sexual contact and infects the vagina and urethra in women and the urethra in men. Because it can't survive long outside the body, it doesn't spread through toilet seats or casual contact. About 70% of infected people have no signs or symptoms at all CDC, so it passes silently between partners until someone tests positive or develops symptoms.
It's curable with a defined course of medication, and clinics treat it routinely. A diagnosis is common and says nothing about you as a person.
Symptoms
Most people feel nothing. When symptoms do appear, they reflect inflammation of the genital lining caused by the parasite irritating those tissues. Symptoms can come and go, which makes the infection easy to dismiss.
In women
Women may notice itching, burning, redness, or soreness of the genitals, discomfort when urinating, and a clear, white, yellowish, or greenish discharge, often with a fishy smell. The greenish, frothy discharge and odor are the classic clues, though they don't show up in everyone. For a deeper rundown, see our pages on trichomoniasis symptoms and trichomoniasis symptoms in women.
In men
Men are commonly asymptomatic. When symptoms occur, they include itching or irritation inside the penis, burning after urinating or ejaculating, and sometimes a discharge. Because men so often carry it without symptoms, an untreated male partner is a frequent reason the infection bounces back after a woman is cured.
Testing
A nucleic acid amplification test (NAAT) is the preferred way to diagnose trichomoniasis. NAATs detect the parasite's genetic material, so they catch infections that older microscope-based wet mounts miss. A widely used example is the Aptima T. vaginalis assay, with sensitivity around 95–100%. Acceptable specimens include vaginal swabs and female urine.
Testing itself is simple: a urine cup, a self-collected swab, or a quick exam, with results usually back in a few days. It's often free or low-cost at health departments, Planned Parenthood, and Title X clinics. If you've had a possible exposure, the timing of your test matters, so read when to test after exposure before you book, and you can get tested through a clinic or at-home kit. Our guide to trichomoniasis testing & diagnosis walks through what each method detects.
Treatment
Trichomoniasis is treated with a class of antiparasitic drugs called nitroimidazoles, metronidazole and tinidazole. They work by entering the parasite and damaging its DNA, which kills it. The recommended regimen for women is no longer a single dose.
The 2021 CDC guidelines moved women onto a multi-day course because it works substantially better. In a randomized trial, about 19% of women given the old single 2 g dose were still infected at follow-up, versus about 11% on the seven-day course Muzny et al., roughly halving the retest-positive rate. Men still do well on a single dose.
| Who | Recommended regimen | Alternative |
|---|---|---|
| Women | Metronidazole 500 mg orally twice daily for 7 days | Tinidazole 2 g orally, single dose |
| Men | Metronidazole 2 g orally, single dose | Tinidazole 2 g orally, single dose |
A few practical rules make or break the cure:
- Finish the entire course even after you feel better. Stopping early leaves living parasites behind.
- Skip alcohol during treatment and for a period afterward. Both metronidazole and tinidazole can trigger a disulfiram-like reaction with flushing, nausea, vomiting, and a racing heart if you drink.
- Treat all sex partners at the same time. If a partner isn't treated, you'll likely catch it right back; ask your clinician about partner treatment.
- Avoid sex until you and your partners have finished treatment and symptoms have cleared.
Because reinfection is common, the CDC recommends that sexually active women be retested about three months after treatment. The drug didn't fail; re-exposure is the usual culprit.
Prevention
The same basics that prevent other STIs apply here. Correct, consistent condom use every time lowers risk. Routine screening of at-risk groups catches the silent infections, and since most cases are symptomless, testing is how the chain breaks.
- Use condoms every time you have sex, start to finish.
- Get tested routinely if you're sexually active or have a new partner, since symptoms aren't a reliable signal.
- Make sure partners are treated before you resume sex, so you don't trade the infection back and forth.
When to see a clinician
See a clinician if you have genital itching, burning, an unusual discharge or odor, or pain with urination, or if a partner tests positive, even when you feel fine. Pregnant people with symptoms should be evaluated, since trichomoniasis can affect pregnancy. If symptoms persist after you finish treatment, go back, since that usually means re-exposure or a partner who needs treating.