Trichomoniasis
Trichomoniasis is a sexually transmitted infection caused by a tiny parasite called Trichomonas vaginalis. It is less well known than chlamydia or gonorrhoea but can cause unpleasant symptoms and may increase the risk of other STIs.
Symptoms in women may include a frothy, yellow-green vaginal discharge with an unpleasant smell, soreness and itching around the vagina, and pain when urinating or during sex. Many men with trichomoniasis have no symptoms, though some may experience pain during urination or ejaculation, and a thin, white discharge.
Diagnosis is usually made via a genital swab. Trichomoniasis is treated effectively with a course of antibiotics, typically metronidazole. Sexual partners should also be treated to prevent reinfection.
Causes of Trichomoniasis
Trichomoniasis is caused by the protozoan parasite Trichomonas vaginalis. It is transmitted through unprotected vaginal sex and is one of the most common curable STIs worldwide.
The parasite infects the lower genital tract in women (vagina, urethra and cervix) and the urethra and, less commonly, the prostate in men.
Risk factors are similar to other STIs and include multiple sexual partners, inconsistent condom use and a history of other STIs. Trichomoniasis is not spread through oral or anal sex, kissing, sharing towels or toilet seats.
Tests that can help check this condition
Learn more on the official NHS page .
Medical review
Dr. Shahzaib Ahmad MBBS, BSc, MRCP, FRCA, FFICM
Clinical Supervisor - Vitall|GMC 7495062|Profile
Reviewed on 22/05/2026
Next review due 22/05/2027
Review focus: Blood biomarkers, laboratory testing methodology, and biochemical interpretation.
