Time to rethink Blastocystis in faecal microbiota transplantation.

Blastocystis commonly colonises the human gut, but its presence has traditionally led to the exclusion of faecal microbiota transplantation donors. Emerging evidence links it to greater microbial diversity and favourable metabolic profiles, while no harm is seen in immunocompetent recipients. Routine screening may be unnecessary, except for subtype-specific testing in immunocompromised patients.