In acute liver failure following hepatitis, toxic insults, or after major liver surgery, there is an increased bacterial translocation from the gut. This may explain some of the infectious complications seen in these conditions. To elucidate mechanisms and find possible preventive measures, we investigated the effect of rectal administration of arginine and probiotic bacteria (Lactobacillus spp.) on bacterial translocation and the extent of liver failure. Sprague-Dawley rats were used and five different Lactobacillus strains (Lb. reuteri R2LC, Lb. rhamnosus DSM 6594 (= strain 271), Lb. plantarum DSM 9843 (= strain 299v), Lb. fermentum 8704:3 (= strain 245), and Lb. reuteri (= strain 108) were administered rectally once daily for 8 days with and without 2% arginine. Acute liver injury (ALI) was induced on the eighth day by intraperitoneal injection of D-galactosamine (1.1 g/kg body weight), and samples were collected after 24 and 48 hours. Bacterial translocation was evaluated by bacterial culture from portal and arterial blood, mesenteric lymph nodes, and liver tissue. Liver enzymes and bilirubin were evaluated in the serum. The bacterial load in the cecum and colon was determined and the liver histopathological changes were studied. There was no mortality at any time. The liver enzymes and bilirubin decreased in some of the groups supplemented with lactobacilli with and without arginine compared with the ALI control group. The incidence of bacterial translocation and the number of the translocated bacteria decreased significantly in some of the supplemented groups. Lb. plantarum + arginine administration significantly reduced the level of the released liver enzymes, hepatocellular necrosis and inflammatory cell infiltration, bacterial translocation, and the number of Enterobacteriaceae in the cecum and colon. Rectal administration of different Lactobacillus strains with and without arginine in an ALI model significantly modulates the extent of the liver failure and reduces bacterial translocation. Lb. plantarum DSM 9843 (= strain 299v) with or without arginine seemed superior to the other Lactobacillus strains. The beneficial effect of arginine administration alone indicates a possible role of nitric oxide and polyamines in this process, and the lactobacilli may execute their action via the same mechanisms or via bacterial antagonism and/or enhancement of systemic and intestinal mucosal immunity.