• Caused by a parasite
  • Common among women but can also affect men

Signs and Symptoms

Most men and many women may not display any symptoms. If symptoms are present, they may include:


  • Yellowish-white, greenish-yellow or grey coloured vaginal discharge

  • Discharge is usually thin, frothy and has a foul odour

  • Itchiness

  • Redness

  • Soreness or pain during sex and when passing urine


  • Slight clear discharge from the penis

  • Itching on the penis

  • Pain when passing urine or after sex


It is important for sexual partners be treated at the same time to prevent re-infecting each other.


Trichomonas may be diagnosed in the following ways:


  • A sample of vaginal discharge is taken to be looked at under a microscope

  • Swabs may also be taken from the cervix


  • The doctor will take swabs of any discharge from the penis and will look at it under a microscope


Trichomonas is not a dangerous infection, however it should be treated right away.  Left untreated, the infection can become very uncomfortable and can make one more susceptible to getting HIV if he/she has sex with a person who is infected with the virus.

Treatment & Prevention

Trichomonas is usually treated with antibiotics called metrondiazole (brand name Flagyl).

WARNING:  Do not drink alcohol when taking metrondiazole.  Alcohol can react with this antibiotic and can cause severe nausea and vomiting.  Alcohol should be avoided for at least two days after treatment has been completed.  To prevent the onset of nausea, it is recommended that this medication be taken with meals.

Pregnancy: If a woman is pregnant or nursing, she should consult with her physician regarding the use of Flagyl.

Even if you are cured, re-infection remains possible. If you have been cured and your partner is infected, (s)he may spread the infection to you again.

Medical Follow-up

You do not need to see your doctor if you took your medication as prescribed and the symptoms have disappeared.

Additional Information

  • Take all of your prescribed medication
  • Do not have sex while you and your partner are being treated
  • Do not drink alcohol while on medication and for two days afterward
  • To relieve itching, soak in a tub or use a cold compress
  • Wear cotton underwear and loose fitting clothing to help speed up healing
  • Get tested! You can have more than one STI and not know it, so it is important to get checked

**If you have any type of infection in the genital area, it is important to inform your partner so that they can also be properly examined and treated if need be**

This information is for general knowledge only and does not replace professional medical advice. For STI testing or more information, contact our confidential sexual health clinic at 519-753-4937 ext. 471.