What Is Trichomoniasis? Symptoms and Treatment
Content last reviewed 2026-09-12 · Educational information — not medical advice
Quick answer
Trichomoniasis is a common STI caused by the parasite Trichomonas vaginalis. It is the most common curable STI, and about 70% of people have no symptoms. Women may notice frothy yellow-green discharge, odor, itching, or burning, and it is cured with a single dose of metronidazole or tinidazole.
What is trichomoniasis?
Trichomoniasis is a sexually transmitted infection caused by a parasite called Trichomonas vaginalis. It is the most common curable STI, and it is estimated that about 70% of people who have it experience no symptoms at all. The parasite lives in the genital tract and is passed between partners during sex. Because it is caused by a parasite rather than a virus or bacterium, it is treated differently from other STIs, and it is fully curable with the right medication.
What are the symptoms of trichomoniasis in women?
In women, trichomoniasis can cause a frothy yellow-green vaginal discharge with a strong odor, along with itching, burning, and pain during urination or sex. The symptoms can range from mild to intense, and they may come and go. Many women have no symptoms at all, which means the infection can go unnoticed and be passed to partners. Because the signs overlap with yeast infections and bacterial vaginosis, testing is needed to tell them apart.
What are the symptoms of trichomoniasis in men?
In men, trichomoniasis usually causes no symptoms at all. When symptoms do appear, they are typically mild and limited to a slight irritation or burning during urination, sometimes described as mild urethritis. Because men rarely notice the infection, they can carry and transmit the parasite without ever knowing. This silent carriage is a major reason trichomoniasis keeps spreading, and it is why partners are treated together even when only one person has symptoms.
How is trichomoniasis transmitted?
Trichomoniasis is transmitted through vaginal sex, specifically penis-to-vagina contact. The parasite can also survive briefly on damp objects, though this is not a common route. Men can carry and transmit the parasite without any symptoms, which makes the infection easy to pass back and forth. Condoms are highly effective against trichomoniasis when used consistently. Because the parasite does not travel through saliva, kissing and oral sex are not routes of transmission.
How is trichomoniasis treated?
Trichomoniasis is cured with a single dose of metronidazole or tinidazole, both taken by mouth. The medication kills the parasite, and symptoms usually improve within days. Sexual partners need treatment at the same time, even if they have no symptoms, or the infection will simply pass back and forth. After treatment, a follow-up test may be recommended to confirm the parasite is gone. Untreated trichomoniasis does not go away on its own.
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Frequently asked questions
Is trichomoniasis curable?
Yes. Trichomoniasis is cured with a single dose of metronidazole or tinidazole, and partners should be treated at the same time.
Can men get trichomoniasis?
Yes. Men can carry and transmit the parasite, usually without any symptoms, which is why partners are treated together.