Routine exploration of the digestive tract is performed under "fasting" condition, without further training. The investigation is limited due to hidroaeric and alimentary content and deep location of some digestive parts (gastric fornix, colon flexures). Oral administration contrast agents cause a distension of the digestive lumen which allows a satisfactory viewing of the "hidden" regions and endoluminal detection of small formations. A combination of conventional and contrast ultrasound brings additional information which increase the overall performance of the ultrasound method.