Increasingly more importance is being ascribed to early detection of colon carcinoma and of its precursor stages, since there has been a practically twofold increase in the incidence of this disease in Germany over the past 20 years. With a combination of 1. case history, 2. rectal palpation result, 3.'blood in stools' test (haemoccult) and 4. coloscopy, many conspicuous changes to the intestinal walls can now be diagnosed at an early stage. Virtual coloscopy represents a gentle, non-invasive alternative to the classical method of coloscopy, while the introduction of the 1.5 meter long endoscope can now be dispensed with. A state-of-the-art computed tomography scanner is used for imaging purposes, thus also providing for assessment of the other abdominal organs.