The symptoms of a trichomonas vaginalis (TV) infection, also known as trichomoniasis, primary affect the genital tract; and therefore may differ between men and women. It’s also possible for the infection to be present, but not cause any symptoms at all.

On this page we’ll discuss:

What are the symptoms of trichomonas vaginalis?

The symptoms caused by trichomoniasis can be similar to those caused by a number of other STIs; and the somewhat common nature of these may make the condition difficult to diagnose.


The Trichomonas Vaginalis parasite can be found in the vagina, urethra and paraurethral glands. Women with TV may experience:

  • an increased amount of vaginal discharge which can also have an unpleasant fishy smell;
  • a change in the consistency of vaginal discharge. It may become thin and frothy or thick and yellow-green in colour;
  • pain when passing urine or when having sex;
  • the area around the vagina becoming inflamed, itchy and sore. This could also extend to the inner thigh area.


The male urethra tends to house the trichomonas vaginalis parasite. The infection can cause the following symptoms in men:

  • a need to urinate more frequently;
  • pain when passing urine or during ejaculation;
  • swelling, soreness or redness noticed around the head of the penis or foreskin;
  • a white, thin discharge from the penis.

Does trichomonas vaginalis always cause symptoms?

No. According to NHS Choices, about half of all male and female cases of trichomoniasis cause no symptoms (in other words, its asymptomatic).

But even if it is asymptomatic, this does not mean that the infection is harmless. When not treated, trichomoniasis increases the risk of contracting other infections, such as HIV. It can also lead to premature birth in pregnant women.

This is why treatment is so important; to reduce the risk of complications, and to prevent the infection from being passed on to someone else.

Can trichomonas vaginalis be mistaken for other STIs?

Yes. The symptoms described above can also be caused by several other STIs, which means that trichomoniasis can potentially be confused with other conditions such as gonorrhoea or chlamydia.

A diagnosis can be made following a genital examination by a doctor or sexual health specialist. The results of a swab from the vagina or penis can be used to confirm TV infections, as can a urine sample.

Doctors are in some cases able to prescribe TV treatment prior to receiving a positive laboratory test result, if for example symptoms strongly indicate TV, or if someone’s partner has had a positive test result.

How is trichomonas vaginalis treated?

In most cases trichomoniasis can be easily treated with oral antibiotics. The drug metronidazole is usually prescribed as a course for between five and seven days or as a one-off, larger dose. It is important, until at least two weeks after completing treatment, to refrain from having sex to minimise the risk of passing the infection onto your sexual partners.

Treatment for trichomoniasis does not make you immune to getting infected again, therefore it is possible to contract the infection on numerous occasions if safe-sex precautions are not taken.

When you receive a diagnosis of TV you should inform your current or recent sexual partners. They will need to be tested and may require treatment. If you fail to inform your sexual partners then there is a chance you may be reinfected.

Can a trichomonas vaginalis infection clear up without treatment?

It is unlikely that a TV infection will resolve on its own. If you think you may have come into contact with an STI or you’re concerned about some symptoms then you should attend your GP or local genitourinary medicine (GUM) clinic.

Page last reviewed:  07/10/2020 | Next review due:  10/10/2022