AIM: To study the effect of probiotics on interleukin-8 secretion in intestinal epithelia when stimulated by METHODS: Colonic adenocarcinoma HT29 cells were cultured and divided into four groups: control, TNF-α (group T in short),bifidobacterium (group B), lactobacillus (group L). B. Longum and L. bulgaricus were suspended in culture medium with a concentration of 1x108 cfu/ml and added into 24 wells respectively. One hour later TNF-α (10 ng/ml) was added into each well of groups T, B, L. The supatants were collected and measured for IL-8 after 3 hours, nucfear factorκB (NF-κB) p65 was also examined by West blotting.RESULTS: There was less interleukin-8 secretion in HT29 cells when preincubated with B. Longum or L. bulgaricus compared with group T. Less p65 appeared in nuclei in groups B and L compared with group T, as detected by West blot.CONCLUSION: Probiotics can suppress interleukin-8 secretion in intestinal epithelia when stimulated by proinflammatory cytokines, which is most likely mediated by NF-κB.