A breakdown in intestinal barrier function and increased bacterial translocation are key events in the pathogenesis of sepsis and liver disease. Altering gut microflora with noninvasive and immunomodulatory probiotic organisms has been proposed as an adjunctive therapy to reduce the level of bacterial translocation and prevent the onset of sepsis. The purpose of this study was to determine the efficacy of a probiotic compound in attenuating hepatic and intestinal injury in a mouse model of sepsis. Wild-type and interleukin-10 (IL-10) gene-deficient 129 Sv/Ev mice were fed the probiotic compound VSL#3 for 7 days. To induce sepsis, the mice were injected with lipopolysaccharide (LPS) and D-galactosamine (GalN) in the presence and absence of the peroxisome proliferator-activated receptor gamma (PPAR␥) inhibitor GW9662. The mice were killed after 6 hours, and their colons were removed for the measurement of the cytokine production and epithelial function. The functional permeability was assessed by the mannitol movement and cyclic adenosine monophosphate-dependent chloride secretion in tissue mounted in Ussing chambers. The livers were analyzed for bacterial translocation, cytokine production, histological injury, and PPAR␥ levels. The tissue levels of tumor necrosis factor alpha, interferon gamma, IL-6, and IL-12p35 ribonucleic acid were measured by semiquantitative reverse transcription polymerase chain reaction. L iver dysfunction and failure contribute to the high mortality rates seen in patients with Gram-negative sepsis. The presence of lipopolysaccharide (LPS) from Gram-negative bacteria in the systemic circulation results in the activation of the innate immune system and the secretion of high levels of proinflammatory cytokines. In animal models, LPS challenge can induce a systemic reaction resulting in a sepsis-like condition characterized by fever, hypotension, and widespread tissue damage. D-Galactosamine (GalN) increases the susceptibility of mice to LPS-induced shock by impairing liver metabolism. 1 Challenging mice with low doses of LPS in conjunction with GalN results in massive liver apoptosis and increased mortality.Tumor necrosis factor alpha (TNF-␣) plays a central role in the overwhelming systemic inflammatory response to LPS. 2 However, the complete blockade of TNF-␣ production does not improve survival in animals or humans 3 The activation of nuclear factor kappa B (NF-B) has been shown to play a key role in the pathogenesis of sepsis and is a pivotal step in the regulation of several immune and proinflammatory genes, including TNF-␣. 4 The modulation of NF-B activity has been proposed as a strategy for reducing the mortality associated with sepsis. Peroxisome proliferator-activated receptor gamma (PPAR␥) is a nuclear hormone receptor and transcription