We report a high prevalence of Dientamoeba fragilis in faecal samples collected from patients attending complimentary medicine practitioners in the British Isles. Specimens were collected directly after passing into sodium acetate-acetic acid-formalin (SAF). During two observation periods in 2002 - 2004 and 2005 – 2007 we recorded a Dientamoeba fragilis prevalence of 14.6% (n=543) and 16.9% (n=421) respectively. These results confirm a surprisingly high prevalence of Dientamoeba fragilis amongst a selected population. Clinical information was only available for half of the patients with Dientamoeba fragilis. 50% of requests with clinical information reported gastrointestinal symptoms. For further work on its pathogenic role and prevalence amongst patients with gastrointestinal symptoms immediate collection in SAF should be considered the optimal sampling modality for UK based laboratories.