Literature data and the results of own examinations of speed and differentiation of stomach evacuation of test breakfasts consisted of different nutrients were presented. The relation of evacuation speed, antegrade and retrograde gastro-duodenal passage to digestive fermentative potential of gastro-duodenal complex was shown. It was concluded about the possibility of it's system characterizing by the ultrasonographical examination of speed and character of test breakfast's evacuation from the stomach.