Trichomoniasis: Symptoms, Causes, Diagnosis and Treatment — What You Need to Know
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD | Last reviewed: October 7, 2026
Quick Answer
Trichomoniasis is a common sexually transmitted infection caused by the parasite Trichomonas vaginalis [1]. Women may have foul-smelling, frothy discharge with burning or itching, while men rarely have symptoms [1]. It is curable with antibiotics, but all partners must be treated at the same time and alcohol avoided [2]. Untreated, it can last for months to years and raises HIV risk [1].
What the research says
A 7-day course of metronidazole cleared trichomoniasis more often than a single dose in women. In a randomized trial of 623 women (311 given one 2 g dose, 312 given 500 mg twice daily for 7 days), 11% of the 7-day group (34 of 312) still tested positive 4 weeks after treatment, versus 19% of the single-dose group (58 of 311; relative risk 0.55, 95% CI 0.34–0.70). Side effects were similar between groups, with nausea the most common (23%), and the authors concluded that the 7-day regimen should be preferred for women (Kissinger et al., The Lancet Infectious Diseases, 2018) [3].
Having trichomoniasis raises the chance of acquiring HIV by about 50%. A systematic review and meta-analysis of 11 studies reporting hazard ratios, all carried out in sub-Saharan Africa, found that people infected with Trichomonas vaginalis were 1.5 times more likely to acquire HIV than uninfected people (95% CI 1.3–1.7; p<0.001) (Masha et al., Sexually Transmitted Infections, 2019) [4].
Where in the Body Does Trichomoniasis Strike?
The parasite that causes trichomoniasis most often infects the lower genital tract [1]. In women, that means the vagina, the outer part of the genitals called the vulva, the opening of the uterus called the cervix, and the urinary opening called the urethra. In men, it infects the inside of the penis, the urethra [1].
The parasite passes between people during genital contact, including vaginal, oral or anal sex [1]. It most often passes from a penis to a vagina, or from a vagina to a penis. It also can pass from a vagina to another vagina [1]. Sex without a condom and genital touching can spread it.
When Do Trichomoniasis Symptoms Start?
Symptoms may start about 5 to 28 days after you get the infection [1]. Or they may start later. Many people don’t have symptoms at all [1]. This is an important fact: the parasite can be spread even if you don’t have symptoms [1], which is why partner testing and treatment matter so much.
What Does Trichomoniasis Look Like in Women?
In women, symptoms include a thin or frothy discharge from the vagina [1]. This fluid has a foul smell, and it might be clear, white, yellow or green. Other symptoms include genital burning, soreness, itching or a change in skin color. Pain with urination or sex is also possible, along with pain in the lower stomach area [1].
What Does Trichomoniasis Look Like in Men?
In men, trichomoniasis rarely causes symptoms. But when symptoms happen, they can include itching or irritation inside the penis, burning with urination or after the penis releases semen, and a clear or pus-like discharge from the penis [1].
Symptom | In women | In men |
Discharge | Thin or frothy, foul-smelling; clear, white, yellow or green | Rare; clear or pus-like from the penis |
Burning or itching | Genital burning, soreness, itching or skin-color change | Itching or irritation inside the penis |
Pain | Pain with urination or sex; pain in lower stomach area | Burning with urination or after releasing semen |
How common | Symptoms do occur | Symptoms are rare |
When Should You See a Doctor?
See your healthcare professional if you have any symptoms of trichomoniasis. Also talk with your healthcare professional if you become aware that a sexual partner has the infection [1].
Trichomoniasis can raise the risk of getting or spreading other sexually transmitted infections, including HIV [1]. And pregnant people who have trichomoniasis might be at higher risk of having their babies early. This is called premature birth [1].
What Causes Trichomoniasis?
Trichomoniasis is caused by a tiny parasite called Trichomonas vaginalis [1]. It is not caused by bacteria or viruses. It is a single-celled parasite, and certain antibiotics are used specifically because they work against this parasite, even though antibiotics are best known for treating bacterial infections.
Who Is Most at Risk?
The main risk factors are behavioral, which means they are also the main things you can change.
Risk factor | Why it matters |
Sex without a condom [1] | The parasite passes through genital contact without a barrier |
More than one sexual partner at a time [1] | More exposures raise the chance of contact with the parasite |
A history of other STIs [1] | Past infection signals higher exposure risk |
A past bout of trichomoniasis [1] | Previous infection means re-exposure is possible |
Douching [1] | Washing or cleaning the vagina with water or fluid mixtures disturbs its natural protection |
Drinking too much alcohol or using drugs [1] | Habits that can lead to risky behavior raise STI risk |
Why Does Trichomoniasis Matter If It’s Curable?
Because an untreated infection can last for months to years [1], the complications add up over time. Trichomoniasis causes inflammation (swelling) in the genital area, which may make it easier for other STIs to enter the body or be passed to others [1]. It also seems to make it easier to become infected with HIV, the virus that can lead to AIDS.
Pregnancy carries specific risks. Pregnant people who have trichomoniasis might deliver their babies too early (premature birth), have a baby with a low birth weight, or give the infection to the baby as it passes through the birth canal [1].
Trichomoniasis is also linked with higher risks of several inflammatory and longer-term conditions:
Linked complication | What it is |
Prostate or cervix cancer [1] | Higher cancer risk in these organs is linked to the infection |
Prostatitis | Swelling of the prostate gland [1] |
Epididymitis [1] | Swelling of the epididymis, the coiled tube above and behind the testicles that stores and transports sperm |
Cystitis [1] | Swelling of the bladder |
How Is Trichomoniasis Diagnosed?
Your healthcare professional may diagnose trichomoniasis with an exam of the genitals and lab tests [2]. The most direct test uses a cotton swab to collect a sample of fluid from your vagina or penis. The sample is then checked under a microscope. If the parasite can be seen, no other tests are needed [2].
If the test doesn’t show the parasite, your healthcare professional still may think you could have trichomoniasis. When this happens, other tests may be done. A lab can do genetic testing of your fluid sample. Or the lab can find out if the parasite can be grown in a sample of your genital discharge or urine. This is called a culture test [2].
If you have trichomoniasis, your healthcare professional likely will test you for other sexually transmitted infections as well [2]. That way, you can get treatment for any other diseases that are found.
How Is Trichomoniasis Treated?
Treatment involves taking medicine called an antibiotic. Options may include one large dose taken by mouth, or several lower doses taken over a week.
One large dose. Your healthcare professional may have you take one dose of medicine by mouth. Antibiotics that treat trichomoniasis include metronidazole, tinidazole and secnidazole [2]. Metronidazole can be taken during pregnancy. Tinidazole and secnidazole usually are not given to pregnant people, as more research is needed on their safety during pregnancy [2].
More than one dose. Your healthcare professional may recommend a few lower doses of metronidazole or tinidazole, taken two times a day for seven days [2].
Why Finishing the Medicine Matters
To help get rid of the infection, keep taking the medicine for the full time prescribed. Take it exactly as prescribed even if you start to feel better after a few days [2]. If you stop using this medicine too soon, your infection may not go away completely.
The Alcohol Rule
Drinking alcohol during and for a few days after treatment can cause upset stomach and vomiting [2]. Don’t drink alcohol for 72 hours after taking metronidazole or tinidazole, or 48 hours after taking secnidazole [2].
Why Both Partners Must Be Treated
All sex partners need treatment at the same time [2]. This keeps you from getting the infection again, also called reinfection. Do not have sex until you and your partner have finished the treatment and the symptoms have gone away [2]. Tell your healthcare professional if symptoms don’t go away after treatment [2].
Treatment element | What to do |
Single-dose option | One large dose by mouth (metronidazole, tinidazole or secnidazole) |
Multi-dose option | Lower doses two times a day for 7 days (metronidazole or tinidazole) |
During pregnancy | Metronidazole can be used; the other two usually are not given |
Finish the course | Take the full prescribed time, exactly as prescribed |
No alcohol | 72 hours after metronidazole or tinidazole; 48 hours after secnidazole [2] |
Partners | All partners treated at the same time; no sex until treatment finishes and symptoms are gone |
Will You Be Tested Again After Treatment?
Your healthcare professional may test you for trichomoniasis once more after treatment. This is done to check whether the infection is gone and that you haven’t gotten infected again. Women often are tested 3 weeks to 3 months after treatment [2]. Men usually are not tested again unless they have trichomoniasis symptoms [2].
Even if you’ve had treatment that gets rid of trichomoniasis, it doesn’t protect you for life [2]. You can get trichomoniasis again if you’re exposed to someone with the infection.
How Can You Prevent Trichomoniasis?
You can prevent trichomoniasis by not having sex [1]. Or, if you’re sexually active, you can take these steps to lower your risk:
Get tested for sexually transmitted infections. Ask any sexual partners to get tested too, then talk about your results.
Think about choosing to be in a long-term relationship with a partner who also doesn’t have trichomoniasis [1].
Use condoms correctly each time you have sex, and put a condom on before the penis touches the vagina, mouth or anus [1].
Don’t douche. Douching removes some healthy bacteria in the vagina that help prevent infections [1].
Don’t drink too much alcohol or use illegal drugs, since heavy drinking or drug use might lead to risky behavior that raises STI risk.
How should you prepare for a trichomoniasis appointment?
Your family healthcare professional or gynecologist can diagnose and prescribe treatment for trichomoniasis. So can a medical practitioner at an urgent care center [2]. Before the appointment, make a list:
Prepare | What to do |
Symptoms list | Detailed description, including when they started |
STI history | Any sexually transmitted infections you’ve had |
Partner history | Number of sexual partners during the past few years |
What to expect | Possible pelvic exam; urine or fluid sample collected for testing |
Your healthcare professional may do a pelvic exam to check your lower genital tract, including your vagina. A sample of urine or other fluid may be collected from inside your vagina or penis for testing [2].
Conclusion
Trichomoniasis is one of the most common curable sexually transmitted infections, a parasite you can get rid of with antibiotics. The catch is that it often causes no symptoms, especially in men, so it spreads silently. If you have any symptoms, or if a sexual partner has the infection, get tested. Treatment is simple, but it works only when every partner is treated at the same time, the full medicine course is finished, and alcohol is avoided during treatment.
What are the next steps for trichomoniasis?
If you notice unusual discharge, burning or itching, book an appointment with your healthcare professional. A swab test gives an answer quickly, and the cure is available.
Frequently Asked Questions
What is trichomoniasis and what causes it?
It is a common sexually transmitted infection caused by a tiny parasite called Trichomonas vaginalis. The parasite passes between people during genital contact.
How do you get trichomoniasis?
Through vaginal, oral or anal sex without a condom, and through genital touching. It most often passes between a penis and a vagina, but it also can pass from a vagina to another vagina.
How long after sex do symptoms start?
Symptoms may start about 5 to 28 days after infection, or they may start later.
What does trichomoniasis look like in women?
A thin or frothy vaginal discharge with a foul smell, clear, white, yellow or green, plus genital burning, soreness, itching or a skin-color change, pain with urination or sex, and lower stomach pain.
Do men get trichomoniasis symptoms?
Rarely. When they do occur, symptoms include itching or irritation inside the penis, burning with urination or after releasing semen, and a clear or pus-like discharge.
Can you spread trichomoniasis without symptoms?
Yes. The parasite can be spread even when a person doesn’t have symptoms, which is why partner testing matters.
Is trichomoniasis curable?
Yes. Treatment involves taking antibiotic medicine, such as a single large dose or several lower doses taken twice daily for seven days.
Can trichomoniasis go away on its own?
Without treatment, the infection can last for months to years. Treatment is the reliable way to clear it.
Can you drink alcohol while being treated?
No. Alcohol during and for a few days after treatment can cause upset stomach and vomiting. Avoid alcohol for 72 hours after metronidazole or tinidazole, or 48 hours after secnidazole.
Why do both partners need treatment?
All sex partners need treatment at the same time to prevent reinfection, which means getting the infection again from an untreated partner.
When can you have sex again after treatment?
Do not have sex until you and your partner have finished the treatment and the symptoms have gone away.
Can trichomoniasis be treated during pregnancy?
Yes. Metronidazole can be taken during pregnancy. Tinidazole and secnidazole usually are not, because more research is needed on their safety.
Why is trichomoniasis a concern during pregnancy?
Pregnant people with the infection might deliver too early (premature birth), have a baby with a low birth weight, or pass the infection to the baby as it passes through the birth canal.
Does trichomoniasis affect HIV risk?
Having the infection causes genital inflammation that may make it easier for other STIs to enter the body, and it seems to make it easier to become infected with HIV.
What are the long-term complications?
Without treatment the infection lasts months to years, and it is linked with higher risks of prostate or cervix cancer, prostatitis, epididymitis and cystitis.
How is trichomoniasis tested for?
A cotton swab collects fluid from the vagina or penis, which is checked under a microscope. If the parasite isn’t seen, genetic testing or a culture test may follow.
Will I be tested again after treatment?
Possibly. Women often are tested 3 weeks to 3 months after treatment. Men usually are not retested unless they have symptoms.
Can you get trichomoniasis again after being cured?
Yes. Treatment doesn’t protect you for life. You can get it again if you’re exposed to someone with the infection.
How can you prevent trichomoniasis?
Not having sex, or using condoms correctly every time, getting tested along with partners, avoiding douching, and limiting alcohol and drug use that can lead to risky behavior.
What should I bring up at my appointment?
A detailed description of your symptoms and when they started, any STIs you’ve had, and the number of sexual partners you’ve had in the past few years.
Related Reading
Pap Smear (Pap Test): Age, Procedure, Results and How Often to Get One: A Pap smear screens for cervical cancer, and the cervical cell sample can sometimes also reveal trichomonas.
Learn more in our guide to STD Testing (STI Testing): Who Needs It, Test Types and What Results Mean.
Bacterial Vaginosis (BV) Test: How It's Done, Types and What Results Mean explains how BV is tested and what results mean.
Sources
Mayo Clinic Staff. Trichomoniasis - Symptoms and causes. Mayo Clinic. December 16, 2025. https://www.mayoclinic.org/diseases-conditions/trichomoniasis/symptoms-causes/syc-20378609
Mayo Clinic Staff. Trichomoniasis - Diagnosis and treatment. Mayo Clinic. December 16, 2025. https://www.mayoclinic.org/diseases-conditions/trichomoniasis/diagnosis-treatment/drc-20378613
Kissinger P, Muzny CA, Mena LA, et al. Single-dose versus 7-day-dose metronidazole for the treatment of trichomoniasis in women: an open-label, randomised controlled trial. Lancet Infect Dis. 2018;18(11):1251-1259. PMID 30297322. https://doi.org/10.1016/S1473-3099(18)30423-7
Masha SC, Cools P, Sanders EJ, et al. Trichomonas vaginalis and HIV infection acquisition: a systematic review and meta-analysis. Sex Transm Infect. 2019;95(1):36-42. PMID 30341233. https://doi.org/10.1136/sextrans-2018-053713
Medical disclaimer
This article is for general educational purposes and is not a substitute for professional medical advice, diagnosis or treatment. If you have symptoms or concerns, consult a qualified healthcare professional. Urgent symptoms should be evaluated by a clinician promptly.
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