Trichomoniasis

Key facts

• Trichomoniasis is one of the most common sexually transmitted infections, caused by the single-celled parasite Trichomonas vaginalis, and is highly curable with a short antiparasitic course.
• Women often notice a frothy, yellow-green discharge with an unpleasant odour, itching or discomfort passing urine; men are usually symptom-free, which is why it spreads silently.
• Treatment uses oral antiparasitics: tinidazole as a single high dose, or ornidazole over a short course; avoid alcohol during and for at least 72 hours after.
• Both partners must be treated at the same time to prevent re-infection.

Recognising the infection

Symptoms vary widely. Women often notice a frothy, yellow-green vaginal discharge with an unpleasant odour, along with itching, soreness, or discomfort during urination or sex. Men are usually asymptomatic, a key reason the infection spreads unnoticed; where symptoms do appear they may include irritation inside the penis or a mild discharge.

How trichomoniasis is treated

Treatment centres on oral antiparasitic medicines from the antiparasitics group. Tinidazole is commonly given as a single high dose, making adherence simple, and ornidazole is an alternative over a short course. Both are nitroimidazoles that disrupt the parasite's DNA. Avoid alcohol while taking either and for at least 72 hours afterwards, as the combination can cause severe nausea.

When to see a doctor

Sexual partners should be treated at the same time even without symptoms, and penetrative sex avoided until both have completed treatment and any symptoms have cleared. See a clinician for testing if you have symptoms or a partner has been diagnosed.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.