After transit through the small intestine barium enters the large intestine and its characteristics in that gut segment can be studied. The pattern of distribution of barium in the colon is always altered in patients with malabsorption syndromes. The physical basis for this alteration is analysed in a manner analagous to that used in soil mechanics. The dispersal of barium granules within the liquid-solid content of the colon is related to certain factors among which is the polarisation and electrical potential of barium particles. A technique using four radiographs which permits evaluation of barium dispersal in the colon - colonic granulometry - is described. Lastly, the authors point out the necessity of classical barium studies in identifying the rare anatomical anomalies that can be the starting point of a typical clinical coeliac syndrome.