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Find out about the symptoms, causes and treatment of trichomoniasis. 

Trichomoniasis is a sexually transmitted infection (STI) caused by a tiny parasite called Trichomonas vaginalis (TV), which infects the vagina and the urethra in both men and women.

Signs and symptoms of trichomoniasis

Up to half of men and women with trichomoniasis will not experience any symptoms and when symptoms do appear, they are often easily confused with other STIs.

If symptoms do appear, it will usually be within a month of coming into contact with the infection.

Symptoms for people with a vagina can include:

  • Vaginal itching, swelling and soreness.
  • A discharge that is unusual for you. It can be frothy and yellow-green coloured and can smell fishy.
  • Lower abdominal pain (tummy).
  • Pain during sex and while weeing.
  • Itchy inner thighs.

Symptoms for people with a penis can include:

  • Thin, white discharge from the penis.
  • Pain during ejaculation and while weeing.
  • Itching, swelling and soreness of the penis.
  • Needing to wee more often.

The causes and spread of trichomoniasis

Trichomoniasis is caused by a tiny parasite called Trichomonas Vaginalis (TV) which affects the vagina and urethra. The infection is easily passed on through having unprotected vaginal sex or sharing sex toys.

It is not known whether it can be passed on by genital contact or by transferring discharge from one vagina to another on the fingers.

You cannot get trichomoniasis from hugging, kissing, sharing cups, plates or cutlery and toilet seats.

Testing for trichomoniasis

Diagnosing trichomoniasis is not easy as it’s symptoms are similar to other STIs.

If a doctor or nurse examines you, they will be looking for red patches on the walls of the vagina and in men, discharge, swelling and soreness from of the head of the penis.

They will also take a swab from your vagina or penis which will be tested for signs of the infection. A swab is taken by brushing a sort of cotton bud or a small plastic loop over the inside of the vagina and head of the penis. It may be a little uncomfortable but shouldn’t be painful. In men, trichomoniasis can also be tested by taking a urine sample.

Test results can be:

  • Point of care testing: results are produced during the appointment
  • Microscope diagnosis: the doctor or nurse may be able to take a look at the sample under a microscope to make a diagnosis during your visit
  • Sent to a lab: the swab may be sent away to a lab, in which case the results normally take a week to come back.

If there is a high chance that you have trichomoniasis (for example if your partner has tested positive), you may be given treatment before the results are back. But be aware that even if your partner tested negative, you could still have it.

You can be tested for trichomoniasis at Brook services, your GP surgery or at GUM or sexual health clinics. Find your nearest using our find a service tool.

Treatment of trichomoniasis

Trichomoniasis is unlikely to go away by itself but without treatment, the infection can last for months but is easily treated with antibiotics. You will often be prescribed an antibiotic called metronidazole which you take for five to seven days.

Metronidazole is very effective but it can make you feel sick and it can’t be mixed with alcohol. In fact, you should wait until 48 hours after finishing your course.

Trichomoniasis is not serious unless you are pregnant when it can cause complications. But don’t worry, it can still be safely treated. Make sure you inform the doctor or nurse if you are (or think you are) pregnant so that they can take this into consideration.

If you had symptoms, you should notice improvements quite quickly. You should go back to where you had your test if:

  • The symptoms don’t improve within a week
  • You have unprotected sex again
  • You had unprotected sex with your partner before the treatment was finished
  • You did not follow the instructions or complete the treatment
  • You vomited after taking the antibiotics
  • The test was negative but you develop signs and symptoms of trichomoniasis

You should also avoid having sex until you have been given the all-clear, to prevent you being re-infected or passing the infection on.


It is important that you tell any recent sexual partners (last six months) that you are being treated for trichomoniasis, so that they go for treatment too.

Some clinics may also offer to contact your partner using what’s called a ‘contact slip’. This is to warn them they may have been exposed and to recommend they get tested and it doesn’t mention your name.


    Other Stuff you might find useful…

    Talking to people about STIs
    Having great sex (safely!)
    12 common mistakes when using condoms
    Penises & testicles
    Talking about condoms with your partner


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