Trichomonas vaginalis

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Trichomonas vaginalis is a sexually transmitted infection (STI). It is sometimes referred to as trichomonas or trichomoniasis, or shortened to TV.

The term trichomonas is used here. This page gives you information about trichomonas, what you can do if you are worried that you might have the infection and advice on how to protect yourself.

Trichomonas Vaginalis (PDF)

Trichomonas vaginalis is a tiny parasite which causes an infection.

In women the infection can be found in the vagina and the urethra (tube where urine comes out).

In men it can be found in the urethra.

The infection is easily passed from one person to another through sexual contact. Anyone who is sexually active can get it and pass it on. You don’t need to have lots of sexual partners.

Trichomonas is usually passed from one person to another during sex. The infection can be spread through unprotected vaginal sex and possibly through sharing sex toys if you don’t wash them or cover them with a new condom each time they are used.

We don’t know if the infection can be spread between women by rubbing vulvas (female genitals) together or by transferring discharge from one vagina to another on the fingers.

It is possible for a pregnant woman to pass the infection to her baby at birth (see below, What happens if I get trichomonas when I’m pregnant?).

You cannot catch trichomonas from oral or anal sex, or from kissing, hugging, sharing cups, plates or cutlery, toilet seats or towels.

Up to half of infected men and women will not have any signs or symptoms at all. Signs and symptoms usually show up within a month of coming into contact with trichomonas. You might notice:


  • Soreness, inflammation and itching in and around the vagina. This can cause discomfort when having sex.
  • A change in vaginal discharge – there may be a small amount or a lot, and it may be thick or thin, or frothy and yellow. You may also notice a strong smell that may be unpleasant.
  • Pain when passing urine.


  • A discharge from the penis, which may be thin and whitish.
  • Pain, or a burning sensation, when passing urine.
  • Inflammation of the foreskin (this is uncommon).

You can only be certain you have trichomonas if you have a test.

A test for trichomonas is usually offered to:

  • women who have signs and symptoms of trichomonas
  • men who have signs and symptoms which have not been caused by other infections such as chlamydia and gonorrhoea
  • men and women whose sexual partner has trichomonas
  • women whose cervical screening test suggests that they may have trichomonas.

You may also wish to discuss with a doctor or a nurse whether you need to have a test if:

  • you have recently had unprotected sex with a new partner
  • you or a partner have had unprotected sex with other partners
  • during a vaginal examination your doctor or nurse notices an unusual discharge or the cervix is red and inflamed
  • a sexual partner tells you they have a sexually transmitted infection
  • you have another sexually transmitted infection
  • you are pregnant or planning a pregnancy.

You could still have trichomonas even if a partner has tested negative – you should not rely on a partner’s negative result.

If you have trichomonas you may wish to be tested for other sexually transmitted infections as you can have more than one sexually transmitted infection at the same time. Having an infection such as trichomonas can mean that you are more at risk of becoming infected with HIV or transmitting it if you are HIV positive.

If you think you might have been in contact with trichomonas you should seek advice straight away. The doctor or nurse can advise you on whether you need a trichomonas test.

If you have trichomonas it is possible for it to show up on the test within a few days after you have had sex.

There are different ways of testing for trichomonas.


  • A doctor or nurse may collect a sample of cells from the vagina during an internal examination.
  • You may be asked to use a swab to collect cells from inside your vagina.


  • A doctor or nurse may use a swab to collect a sample of cells from the entrance to the urethra.

A swab looks a bit like a cotton bud, but is smaller and rounded. It sometimes has a small plastic loop on the end rather than a cotton tip. It is wiped over the parts of the body that could be infected and easily picks up samples of discharge and cells. This only takes a few seconds and is not painful, though it may be uncomfortable for a moment.

Sometimes it may be possible for a specimen to be looked at under the microscope immediately and for you to get the test result straight away. Otherwise, you may have to wait up to 10 days for the result.

Sometimes trichomonas will show up during a routine cervical screening test. If this happens you will be offered a test for trichomonas to confirm you have the infection. This is because the trichomonas result from a cervical screening test is not reliable. If you have had a cervical screening test it does not mean that you have been tested for trichomonas.

Routine blood tests do not detect infections such as trichomonas. If you are not sure whether you have been tested for trichomonas, just ask.

The accuracy of trichomonas tests depends on the kind of test used and whether it is used in men or women. Some types of tests are less accurate in men.

As no test is 100 per cent accurate there is a small chance that the tests will give a negative result when you do have the infection. This is known as a false negative result. This can sometimes explain why you might get a different result when you go to a different clinic to have another test or why you and your partner might get a different test result.

It is very rare for the trichomonas test to be positive when you haven’t got trichomonas.

There are a number of services you can go to. Choose the service you feel most comfortable with. A trichomonas test can be done at:

  • a genitourinary medicine (GUM) or sexual health clinic
  • some general practices – ask a doctor or practice nurse
  • some contraception clinics and young people’s services.

For information on how to find a service see How to get help with your sexual health.

All tests are free through NHS services. Treatment is also free unless you go to your general practice where you may have to pay a prescription charge for the treatment.

  • The treatment involves taking a course of antibiotic tablets either as a single dose or a longer course (up to a week). If you take it according to the instructions it is at least 95 per cent effective.
  • You will be advised not to drink alcohol during the treatment and for 48 hours afterwards. This is because antibiotics used to treat trichomonas react with alcohol and can make you feel very unwell.
  • If there is a high chance you have the infection, treatment may be started before the results of the test are back. You will always be given treatment for trichomonas if your partner is found to have trichomonas.
  • Do tell the doctor or nurse if you are pregnant, think you might be, or are breastfeeding, as this can affect the treatment you are given. Not all women are given treatment during pregnancy. The doctor or nurse will discuss the options with you.
  • There is no evidence that complementary therapies can cure trichomonas.

You should notice an improvement in the signs and symptoms within a few days.

If you develop lower abdominal tenderness see your doctor or nurse as it may be necessary to investigate other possible causes of the pain, including testing for other sexually transmitted infections.

If you take the treatment according to the instructions you will not normally need a follow-up test. You should, however, go back to the clinic if:

  • you think you may have come into contact with trichomonas again
  • you had unprotected sex with a partner before the treatment was finished (see below, How soon can I have sex again?)
  • you did not complete the treatment or did not take it according to the instructions
  • you vomited after taking the tablets
  • the signs and symptoms don’t go away (see above, When will the signs and symptoms go away?)
  • your test was negative but you develop signs or symptoms of trichomonas (see above, What are the signs and symptoms?).

In these situations you may need a repeat test which can be done one week after the first test.You may need another course of antibiotics, a different treatment, or tests for other infections.

If you have had trichomonas and it has been treated you will not be immune to the infection – this means that you can get it again.

You can always go back to the doctor, nurse or clinic if you have any questions or need any advice on how to protect yourself from infection in the future.

If trichomonas isn’t treated you may be at more risk of becoming infected with HIV or transmitting it if you are HIV positive. Trichomonas may also cause problems with a pregnancy (see below, What happens if I get trichomonas when I’m pregnant?). Trichomonas is not thought to affect your fertility.

Trichomonas is unlikely to go away without treatment, however, for some people, trichomonas may cure itself. If you delay seeking treatment you risk passing the infection on to someone else.

It is strongly advised that you do not have any sexual intercourse, including vaginal, anal or oral sex, until you and a partner have both finished the treatment and any follow-up treatment. This is to help prevent you being reinfected or passing the infection on to someone else.

The test cannot tell you how long the infection has been there. If you have had more than one sexual partner it can be difficult to know which partner you got trichomonas from.

If you feel upset or angry about having trichomonas and find it difficult to talk to your partner or friends, don’t be afraid to discuss how you feel with the staff at the clinic or general practice.

If the test shows that you have trichomonas then it is very important that your current sexual partner and any other recent partners are also tested and treated. The staff at the clinic or general practice can discuss with you which of your sexual partners may need to be tested.

You may be given a contact slip to send or give to your partner(s) or, with your permission, the clinic can do this for you. The slip explains that they may have been exposed to a sexually transmitted infection and suggests that they go for a check-up. It may or may not say what the infection is. It will not have your name on it, so your confidentiality is protected. This is called partner notification. You are strongly advised to tell your partner(s), but it isn’t compulsory.

There is no evidence that trichomonas will affect your chances of getting pregnant.

Trichomonas may cause problems with a pregnancy. Some research suggests that it could lead to a premature birth or a baby with a low birth weight.

Trichomonas can be passed to a baby during the birth. This is not common.

If you are pregnant you should tell the doctor or nurse so that they can discuss with you whether it will be helpful to have any treatment.

There is no evidence that trichomonas causes cervical cancer.

It is possible to get trichomonas and other sexually transmitted infections by having sex with someone who has the infection but has no symptoms. The following measures will help protect you from trichomonas and most other sexually transmitted infections including HIV, chlamydia and gonorrhoea. If you have a sexually transmitted infection they will also help prevent you from passing it on to your partner.

  • Use condoms (male or female) every time you have vaginal or anal sex.
  • If you have oral sex, use a condom to cover the penis, or a latex or polyurethane (soft plastic) square to cover the female genitals or male or female anus.
  • Avoid sharing sex toys. If you do share them, wash them or cover them with a new condom before anyone else uses them.
  • If you are not sure how to use condoms correctly see our information on condoms.

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This website can only give you general information about sexually transmitted infections. The information is based on evidence-based guidance produced by The British Association for Sexual Health and HIV (BASHH) and The Faculty of Sexual and Reproductive Healthcare of the Royal College of Obstetricians and Gynaecologists.

Remember – contact your doctor, practice nurse or a clinic if you are worried or unsure about anything.