This study aimed to investigate the effects of lactic acid bacterial fermentation extract (LABEF) on cystitis induced by Escherichia coli lipopolysaccharide (LPS) in the mouse bladder by pathological analyses and measurement of the levels of tumor necrosis factor-alpha (TNF-\u03b1) and interleukin-18 (IL-18). LABEF was administered orally (5 \u03bcg\/L) to mice for 10 days following which, the study group (n = 12) was injected intravesically with 5 \u03bcg\/L LPS. The bladder tissue was then harvested after 24 hours and subjected to hematoxylin and eosin (H-E) staining. A semiquantative score was used to evaluate inflammation (bladder inflammation index; BII). TNF-\u03b1 immunohistochemical staining and multiplex cytokine assay were also performed. TNF-\u03b1 and IL-18 levels were determined. The results were compared with those of the control group (n = 12). The BII in the control and study groups was 2.7 \u00b1 0.5 and 1.1 \u00b1 0.7, respectively, with the control group scores significantly differing from the study group scores (p value < 0.001). TNF-\u03b1 immunohistochemical staining showed similar results. The TNF-\u03b1 levels determined by the multiplex cytokine assay were 2.82 \u00b1 1.35 pg\/mg and 1.55 \u00b1 0.56 pg\/mg for the control and study groups, respectively, and the difference in values between these groups was statistically significant (p value = 0.007). Thus, oral administration of LABEF appears to have a preventive effect against the inflammatory responses and TNF-\u03b1 expression induced by intravesical instillation of LPS in the mouse bladder. Further studies are required to determine the clinical application of this finding.