What Is Trichomoniasis?

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Trichomoniasis is a sexually transmitted disease (STD). It is one one the most common STDs and may be referred to as "trich." The symptoms include itching, irritation and discharge in women, and pain with urination in men. It is caused by a parasite, can be diagnosed with a physical exam and a microscopic analysis, and is treatable with Flagyl (metronidazole), an antimicrobial. 

Trichomaoniasis Symptoms

The symptoms of trichomoniasis may begin between several days to a month after you become infected, and there can even be a delay of several months before symptoms even surface. In fact, the great majority of people do not have symptoms at all, but can still spread the infection to others.

Women are more likely than men to experience symptoms if they become infected with trichomoniasis.

Symptoms in Women

Symptoms in women are usually more noticeable than the symptoms in men. Women generally experience symptoms of trichomoniasis within 1 to 4 weeks of initial infection.


The symptoms of trichomoniasis in women include:

  • Irritation and itching of the vagina and surrounding area
  • Frothy, colored vaginal discharge
  • Strong vaginal odor
  • Pain with intercourse
  • Pain when urinating

Complications in Women

  • Trichomoniasis can negatively affect the outcome of a pregnancy. Pregnant women infected with the parasite are more likely to have a pre-term birth and are more likely to give birth to a low birth weight baby.

Symptoms in Men

Most men with trichomoniasis don’t have any symptoms. When they do, their symptoms are generally mild and include:

  • Pain when urinating
  • Pain when ejaculating
  • Discharge
  • The discomfort of the penis
Symptoms of trichomoniasis.
Nusha Ashjaee / Verywell

Trichomoniasis and HIV

If you have trichomoniasis, you are more susceptible to infection by HIV, the virus that causes AIDS. If you are HIV positive, trichomoniasis also makes it more likely that you will pass HIV to your sexual partners. There is a stronger association between trichomoniasis and HIV for women than there is for men. 


Trichomoniasis affects both men and women and is caused by a single-celled parasitic organism known as Trichomonas vaginalis. The infection is sexually transmitted and can be spread by sexual intercourse as well as by skin-to-skin contact involving the vagina or penis. The parasite is able to live in and around the vagina or inside the penis and is not normally associated with the effects of other areas of the body. It is not spread by shaking hands, touching, or kissing.

How It's Spread

The CDC estimates that more than 2 million people in the United States are infected with trichomoniasis. The more common and prevalent it is, the higher the likelihood of getting the infection. If you have unprotected sex with someone who may be infected, this makes you more likely to contract the infection yourself. 

Effects on the Body

In women, trichomoniasis causes a vaginal infection called vaginitis. In men, it infects the urethra, the tube inside the penis that carries sperm and urine. The parasite invades the layer underneath the skin and produces an inflammatory reaction. The presence of the parasite and the resulting inflammation produces the characteristic itching, pain, discharge, and odor associated with trichomoniasis. 


The symptoms of trichomoniasis are somewhat vague and similar to the symptoms of skin conditions or other STDs. A medical appointment is necessary for a definitive diagnosis, especially because there is a prescription anti-parasitic treatment that can cure the infection. 

How the Organism Is Identified

For both men and women, samples can be tested for the parasite itself, which can be visualized under a microscope. A polymerase chain reaction (PCR) test, which can detect the genetic components of the parasite, may be also used in diagnosing the infection. 

Diagnosis in Women

If you have trichomoniasis, your physical examination may show irritation of the vagina as well as discharge, and there may also be a characteristic odor. Trichomoniasis can also cause irritation of the cervix, which is inside the body and can only be visualized with a medical examination. 

A swab of the vagina or cervix provides a small sample of vaginal secretions. Your healthcare providers can then look at this sample under a microscope. This diagnostic method is called using a wet mount. It can be used to visualize the parasite itself.

The parasite that causes trichomoniasis is not always visible on a wet mount, though. A nucleic acid amplification test (NAAT) can look for the parasite's genetic material to help with diagnosis.

Diagnosis in Men

The physical examination is rarely abnormal in men who have trichomoniasis infection. If you have symptoms of the infection, your healthcare provider may test for the infection using a urine sample or a urethral swab. 


The treatment of trichomoniasis is generally effective if you are otherwise in good health. For women, 500 mg of Flagyl (metronidazole) twice a day for seven days is the recommended regimen, while a single, 2-gram dose of metronidazole is recommended for men. An alternative regimen for both men and women is a single 2-gram dose of Tindamax (tinidazole).

For men and women who were treated and the infection recurred, additional doses are prescribed. Repeating the regimen above is recommended for those whose recurrent infection was due to reexposure from an untreated sex partner.

If the treatment of an initial infection failed and the infection persists, a once-daily, 2-gram dose of metronidazole or tinidazole for seven days is recommended for women. For men, 500 mg of metronidazole twice a day for seven days is recommended.

There are cream and gel forms of metronidazole, but they are generally not effective for treating trichomoniasis.

Trichomoniasis Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Woman

You should not drink alcohol for several days when using these medications as the combination can induce a severe physical reaction characterized by high blood pressure, shortness of breath, nausea, and vomiting. 

After using the medications, it is recommended that you abstain from unprotected sexual activity for a week and until your symptoms are clear. This is because It takes approximately one week for the medication to get rid of the infection. It is also important that you and your sexual partners be treated for trichomoniasis at the same time to reduce the risk of reinfection.


While abstaining from vaginal, oral, and anal sex is the only unfailing way to prevent trichomoniasis infection, consistent and correct usage of condoms has been shown to reduce the risk of infection.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. Trichomoniasis - CDC fact sheet. Reviewed July 22, 2021.

  2. Planned Parenthood. Trichomoniasis (Trich)

  3. Centers for Disease Control and Prevention. Trichomoniasis statistics. Reviewed April 5, 2021.

  4. Van der pol B. Clinical and Laboratory Testing for Trichomonas vaginalis Infection. J Clin Microbiol. 2016;54(1):7-12. doi:+10.1128/JCM.02025-15

  5. Doxtader EE, Elsheikh TM. Diagnosis of trichomoniasis in men by urine cytology. Cancer Cytopathol. 2017;125(1):55-59. doi:10.1002/cncy.21778

  6. Centers for Disease Control and Prevention. Trichomoniasis. Reviewed July 22, 2021.

Additional Reading
Elizabeth Boskey, PhD

By Elizabeth Boskey, PhD
Boskey has a doctorate in biophysics and master's degrees in public health and social work, with expertise in transgender and sexual health.