We studied the effects of oligosaccharides which were obtained from tamarind xyloglucan by cellulase digestion on absorption of 3-O-methyl-D-glucose using the everted sacs from rat small intestine. Among oligosaccharides tested, octasaccharide and nonasaccharide, which contain D-galactose residue at non-reducing terminals, inhibited effectively absorption of 3-O-methyl-D-glucose, and their inhibitory effects were concentration-dependent. On the other hand, heptasaccharide not having D-galactose residue at its non-reducing terminal showed no in-hibitory effect on absorption of 3-O-methyl-D-glucose. These results indicate that the octasaccharide and nonasaccharide may not only serve as a soluble dietary fiber with small molecular weight but also lower the blood sugar level.