A germinated barley foodstuff (GBF) containing glutamine-rich protein and hemicellulose-rich fiber was made from brewer's spent grain, by physical isolation. Our previous studies demonstrated that GBF supported maintenance of epithelial cell populations, facilitated epithelial repair, and suppressed epithelial nuclear factor kappaB-DNA-binding activity through generating increased short-chain fatty acid (especially butyrate) production by luminal microflora, which includes Bifidobacterium and Eubacterium, thereby preventing experimental colonic injury. The fiber fraction also modulates stool water content because of its high water-holding capacity. The patients with mild to moderate active ulcerative colitis who had been unresponsive to or intolerant of standard treatment received 20-30 g GBF, feeding daily in a non-randomized, open-label fashion. At 4 weeks, this treatment resulted in a significant clinical and endoscopic improvement. The improvement was associated with an increase in stool butyrate concentrations. These results indicate that GBF feeding is a potentially new, attractive prebiotic treatment in patients with ulcerative colitis. The potency of GBF on modulating microflora, as well as the high water-holding capacity, may play an important role in treatment and prolongation of remission in ulcerative colitis.