What is it?

Trichomonas is a common sexually transmitted infection (STI) caused by a small organism called Trichomonas vaginalis.  At any given time, up to 35% of people could have a trichomonas infection.  Trichomonas is easily treated with antibiotics.

How is it spread?

Trichomonas is spread through condomless vaginal intercourse with an infected partner.

What are the symptoms?

In up to 50% of cases, you can have no symptoms but can still pass trichomonas to someone else without knowing it.  Symptoms can appear from 4 to 28 days after contact and may include the following:

  • Vaginal infection: Individuals with symptoms may notice increased vaginal discharge that may be yellow or off-white in colour.  It is usually watery, frothy, or bubbly and may smell bad.  This discharge may cause itchiness, redness, and soreness. Abnormal vaginal bleeding may also occur such as bleeding immediately after vaginal penetration. You may also experience abdominal or pelvic pain. Vaginal intercourse and urination may be painful. If you are having urinary tract infection symptoms, it is also recommended that you test for sexually transmitted infections such as chlamydia, gonorrhea, and trichomonas.
  • Urethral/penile infection: Individuals often have no symptoms but those with symptoms may notice a burning feeling during urination, or irritation/ redness at the urethral opening.


 How is it diagnosed?

Testing is done with a swab or urine sent to a laboratory for testing.   Trichomonas can also be diagnosed through a Pap test.  A urine test for people with penises is awaiting approval from Health Canada, so in the future, such partners can be tested and treated.

What are the complications?

Trichomonas is rarely dangerous but it can be uncomfortable.  In rare cases, untreated trichomonas can lead to vulvovaginitis (inflammation and irritation of the vulva and vagina) and this may contribute to pelvic inflammatory disease (PID). If you are pregnant or suspect that you are pregnant, possible though rare,  reproductive complications may include increased risk for infections, post-caesarean infection, premature rupture of membranes and pre-term birth. Trichomonas infection can also increase your risk of contracting HIV.

How is it treated?

The most effective treatment for trichomonas is a drug called metronidazole or Flagyl.  A single dose of Flagyl taken orally cures over 90% of cases.  Flagyl can cause nausea and vomiting, especially in combination with alcohol.  Flagyl is safe in pregnancy.

What about sexual partners?

All sexual partners within the past two months should be treated.  They should be treated even if their tests results are negative.  If you have not had sex in the past two months, your last partner(s) should be tested and treated.  Inform your partner(s) that not having symptoms does not mean that they do not have trichomonas.

 How is it prevented?

Using a condom will greatly reduce the possibility of being infected with trichomonas or other sexually transmitted infections.