Effect of xylooligosaccharide intake on severe constipation in pregnant women.

Xylooligosaccharides (XOS) are mainly composed of two or three xylose units with beta-1,4 linkages. They are obtained by hemicellulose hydrolysis, which is relatively abundant in the cell walls of grains. XOS increases the number of intestinal Bifidobacterium in humans, and maintains the fecal water content within the normal range.