The organism Trichomonas vaginalis is a sexually transmissible protozoal parasite. It is the commonest curable sexually transmitted infection (STI); The World Health Organization estimates that about 170 million new cases occur annually.1 It is a common cause of vaginal discharge in women, in whom it may also cause vulval irritation and inflammation, dysuria, and inflammation of the exo-cervix. It has been associated with dysuria and urethral discharge in men but asymptomatic infection also occurs in both sexes. T vaginalis infection is associated with low socioeconomic status, and is more prevalent in developing than in developed countries.2,3 Opinions vary concerning whether or not T vaginalis can be transmitted by non-sexual contact.4,5 A morphologically similar organism, Pentatrichomonas hominis , is a commensal of the human large intestine, but conventional wisdom has it that this organism does not multiply in the human reproductive tract. Microscopy of a wet mount preparation is the most commonly used diagnostic test for T vaginalis infection. Characteristic motile flagellated protozoa are readily seen. Microscopy for T vaginalis should be performed as soon as possible after the sample is taken as motility diminishes with time. Wet …