AIM: To investigate the effects of probiotic on intestinalmucosae of patients with ulcerative colitis (UC),and toevaluate the role of probiotic in preventing the relapse of UC.METHODS: Thirty patients received treatment withsulphasalazine (SASP) and glucocorticoid and then wererandomly administered bifid triple viable capsule (BIFICO)(1.26 g/d),or an identical placebo (starch) for 8 wk.Fecalsamples were collected for stool culture 2 wk before andafter the randomized treatments.The patients wereevaluated clinically,endoscopically and histologically after2 mo of treatment or in case of relapse of UC.p65 and I_kBexpressions were determined by Western blot analysis.DNA-binding activity of NF-_kB in colonic nuclear extractswas detected by electrophoretic mobility shift assay(EMSA).mRNA expressions of cytokines were identifiedby semi-quantitative assay,reverse transcriptase-polymerase chain reaction (RT-PCR).RESULTS: Three patients (20%) in the BIFICO group hadrelapses during 2-mo follow-up period,compared with14 (93.3%) in placebo group (P<0.01).The concentrationof fecal lactobacilli,bifidobacteria was significantlyincreased in BIFICO-treated group only (P<0.01).Theexpressions of NF-_kB p65 and DNA binding activity of NF-_kB were significantly attenuated in the treatment groupthan that in control (P<0.05).The mRNA expression ofanti-inflammatory cytokines was elevated in comparisonwith the control group.CONCLUSION: The probiotic could impede the activationof NF-_kB,decrease the expressions of TNF-α and IL-1βand elevate the expression of IL-10.These results suggestthat oral administration of this new probiotic preparationis effective in preventing flare-ups of chronic UC.It maybecome a prophylactic drug to decrease the relapse of UC. AIM: To investigate the effects of probiotic on intestinal mucosae of patients with ulcerative colitis (UC), and to evaluate the role of probiotic in preventing the relapse of UC. METHODS: Thirty patients received treatment with sulphasalazine (SASP) and glucocorticoid and then were administered randomly bifid triple viable capsule (BIFICO) (1.26 g / d), or an identical placebo (starch) for 8 wk. Fecalsamples were collected for stool culture 2 wk before andafter the randomized treatments.The patient wereevaluated clinically, endoscopically and histologically after 2 mo of treatment or in case of relapse of UC.p65 and I_kBexpressions were determined by Western blot analysis. DNA-binding activity of NF-_kB in colonic nuclear extracts was detected by electrophoretic mobility shift assay (EMSA). mRNA expressions of cytokines were identified by semi-quantitative assay, reverse transcriptase-polymerase chain reaction (RT-PCR) .RESULTS: Three patients (20%) in the BIFICO group hadrelapses during 2-mo follow-up The concentration of fecal lactobacilli, bifidobacteria was significantly increased in BIFICO-treated group only (P <0.01). The expression of NF-κB p65 and DNA binding activity of NF- _kB were significantly attenuated in the treatment groupthan that in control (P <0.05). The mRNA expression of anti-inflammatory cytokines was elevated in comparison with the control group. CONCLUSION: The probiotic could impede the activation of NF-_kB, decrease the expressions of TNF- α and IL-1βand elevate the expression of IL-10. These results suggest that oral administration of this new probiotic preparations have effective in preventing flare-ups of chronic UC. It maycome a prophylactic drug to decrease the relapse of UC.