The role of the colonic bacterial flora as scavenger of carbohydrate (CHO) in general and that of fruit juice in particular is reviewed. In the large bowel, CHO is fermented to short chain fatty acids (SCFA) and gas. SCFA are not produced in the immediate neonatal period when the fecal flora is still at the first stage of its development. Studies have demonstrated that mature animals have a compensatory response to diarrhea by increasing six times the capacity to absorb fluids in the large bowel compared to the younger animals; furthermore, CHO that arrives in the colon is completely fermented to SCFA while in the younger pigs CHO passes through the colon unchanged. As in the young pigs, a similar situation can occur in young children when a relatively large amount of CHO arrives in the large bowel.