The extent of intestinal absorption and malabsorption may be exactly stated by means of the method "generalized absorption". According to first-hand examinations an alteration of absorbing kinetics of D-xylose dependent on age could have been demonstrated. The velocity of absorption decreases in the elderly and the general absorbing process are prolonged. The extent of absorption restriction in the elderly are under physiological circumstances without clinical value. The health elder man disposes of the same power for a complete absorption of an offered substrate like the younger one. An increasing of cases with a malabsorption in the age may be explained by a increased multmorbidity in the elderly.