Abstract: The invention relates to kits and methods for aiding the diagnosis of Barrett's oesophagus or Barrett's associated dysplasia. Preferred is a method comprising assaying cells from the surface of a subject's oesophagus for a non-squamous cellular marker, wherein detection of such a marker indicates increased likelihood of the presence of Barrett's or Barrett's associated dysplasia, preferably wherein said sample of cells is not directed to a particular site within the oesophagus. The invention also encompasses a method comprising sampling the cellular surface of the oesophagus of said subject. The invention also relates to a kit comprising a swallowable device comprising abrasive material capable of collecting cells from the surface of the oesophagus, together with printed instructions for its use in detection of Barrett's oesophagus or Barrett's associated dysplasia. Preferably said device comprises a capsule sponge.