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Health Information Center


  • Cynthia M. Johnson, MA
Publication Type:




Trichomoniasis is a sexually transmitted infection (STI).


Trichomoniasis is caused by a parasite. An infected person can pass it on to his or her partner during sex.

Risk Factors

Trichomoniasis is more common in women. The risk may be higher for those who:

  • Have more than one sex partner
  • Do not use condoms during sex
  • Have had STIs before


Some people may not have symptoms of trichomoniasis. Others may have:

In women:

  • A bad-smelling, greenish-yellow discharge from the vagina
  • Pain, itching, or burning of the genitals
  • Bleeding after sex
Infection Site in Women.

Vaginahttp://services.epnet.com/getimage.aspx?imageiid=75297529si2081.jpgsi2081.jpgNULLjpgsi2081.jpgNULL\\hgfiler01a\intellect\images\si2081.jpgNULL41NULL2008-12-10300460Copyright © Nucleus Medical Media, Inc.

In men:

  • Discharge from the penis
  • Itching or pain
  • Pain when passing urine
  • Pain in the testes or scrotum
Infection Site in Men.

Male Urethtrahttp://services.epnet.com/getimage.aspx?imageiid=75347534si2189.jpgsi2189.jpgNULLjpgsi2189.jpgNULL\\hgfiler01a\intellect\images\si2189.jpgNULL107NULL2008-12-10352540Copyright © Nucleus Medical Media, Inc.


The doctor will ask about symptoms and health history. You will also be asked about your sexual history. A physical exam will be done. A pelvic exam may also be done.

Tests will be done to look for signs of infection, such as:

  • Women—testing fluid or discharge from the vagina
  • Men—testing urine, semen, or discharge from the penis


The infection is treated with antibiotics. Sex partners may also need treatment.


The risk of trichomoniasis may be lowered by:

  • Always using condoms during sex
  • Only having sex with one person who does not have an STI




  • Mercer F, Johnson PJ. Trichomonas vaginalis: pathogenesis, symbiont interactions, and host cell immune responses. Trends Parasitol. 2018;34(8):683-693.
  • Sexually transmitted diseases. National Institute of Allergy and Infectious Diseases website. Available at: https://www.niaid.nih.gov/diseases-conditions/sexually-transmitted-diseases.
  • Trichomoniasis. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/std/trichomonas/STDFact-Trichomoniasis.htm.
  • Trichomoniasis. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/trichomoniasis.


  • David L. Horn, MD, FACP
Last Updated:

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.