xylo-oligosaccharide is a kind of prebiological substance, which can' t be digested but can selectively activate bacterial reproduction within intestines. it can obviously improve intestinal micro ecological balance, proliferate bifid bacteria and gastric function. this point has been proved by experimental findings and recognized by more and more people. direct physiological effect 1. low in caloric value and difficult for digestion 2. functioned as water-soluble edible fiber 3. preventive to caries 4. capable of improving blood sugar 5. capable of improving fat metabolism 6. capable of improving intestinal bifid bacteria in both count and activity physiological effect after bifid bacteria are proliferated 1. stimulating the intake and utilization of food and maintaining the normal intestinal function. 2. restoring the normal intestinal colony during anti-biotic treatment, radiotherapy and chemotherapy. 3. improving the diarrhea and constipation and inhibiting the growth of pathogenic bacteria and putrefactive bacteria. 4. improving body immunity and regulating the immunity as immunomodulator. 5. reducing the intestinal putrefactive substances and carcinogenic substances. 6. improving serum indices and lowering the cholesterol level. 7. increasing the intake of calcium, iron and other mineral substances. 8. good for the production of vitamin b in body.