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revised Wednesday April 22 2009
healthy sexuality
Types of Sexually Transmitted Infections ( STIs)


This webpage is for information purposes only and is not a substitute for professional medical advice.

Trichomoniasis is caused by a microscopic parasite called trichomonas vaginalis. It is spread from person to person through vaginal intercourse or by sharing infected towels or bathing suits.

Signs & Symptoms

A Trichomoniasis infection might not cause any symptoms in men or women.

Females might experience:

  • A frothy, green vaginal discharge.
  • An unpleasant odour from the vaginal area.
  • Intense vaginal itching.
  • Redness and pain in vaginal area.
  • Frequent urination.

Males might experience:

  • A discharge from the penis.
  • Pain or burning when urinating.
  • Irritation around the tip of the penis.

Diagnosis & Treatment

Diagnosing Trichomoniasis


Your doctor will perform a pelvic exam to look for swelling and abnormal discharge and take a swab sample from your vagina. The sample will be sent to a lab, where a test will show if trichomonas vaginalis is causing the problem. Occasionally trichomoniasis will appear on a routine Pap test.


Your doctor will take a swab sample from your penis. The sample will be sent to a lab, where a test will show if trichomoniasis is causing the problem. If your partner is diagnosed with trichomoniasis you’ll be treated regardless of your test results.


Flagyl® (metronidazole) is the most effective treatment for trichomoniasis. Your doctor will prescribe pills.

You might feel sick to your stomach or have diarrhea while taking Flagyl®. Other side effects include a persistent, dry metallic taste in the mouth and less vaginal lubrication.

Combining alcohol and Flagyl® will cause you to vomit. Don’t drink wine, liquor, beer or any other alcohol while taking Flagyl® and for 48 hours after finishing treatment.

Don’t have intercourse while you’re being treated. All of your sexual partners must also be treated so you don’t get re-infected.

If you finish your Flagyl® medication and still have symptoms, return to your doctor for more testing and treatment.

Left untreated, trichomoniasis can lead to pelvic inflammatory disease (PID) which can cause infertility.



You can prevent getting or spreading a trichomoniasis infection by:

  • Not having sex.
  • Being tested together with all new partners prior to sexual activity.
  • Always using latex condoms.

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Revised: Wednesday April 22 2009

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