Faecal excretion of cysts known as cyanobacterium-like bodies (CLB) is associated with a diarrhoeal illness, which is often prolonged and severe. It is seen mainly in travellers and immunocompromised patients. Recently these cysts have been shown to be coccidian oocysts. We describe three patients who developed diarrhoea while travelling abroad. Stool samples from all three patients contained CLB. Jejunal aspirates from two patients also yielded CLB. Conventional histology of jejunal biopsy specimens confirmed that two patients had enteritis. Electronmicroscopy of the same biopsy specimens revealed intraepithelial coccidia. These findings suggest that the small bowel is the site of infection of this new coccidian disease.