The intestinal microflora is not only involved in the digestion of nutrients, but also in local immunity, forming a barrier against pathogenic microorganisms. The derangement of the gut microflora may lead to microbial translocation, defined as the passage of viable microorganisms or bacterial products (i.e., LPS, lipopeptides) from the intestinal lumen to the mesenteric lymph nodes and other extraintestinal sites. The most recent evidence suggests that microbial translocation (MT) may occur not only in cirrhosis, but also in the early stage of several liver diseases, including alcoholic hepatopathy and nonalcoholic fatty liver disease. Different mechanisms, such as small intestinal bacterial overgrowth, increased permeability of intestinal mucosa, and impaired immunity, may favor MT. Furthermore, MT has been implicated in the pathogenesis of the complications of cirrhosis, which are a significant cause of morbidity and mortality in cirrhotic subjects. Therapeutic strategies aiming at modulating the gut microflora and reducing MT have focused on antibiotic-based options, such as selective intestinal decontamination, and nonantibiotic-based options, such as prokinetics and probiotics. In particular, probiotics may represent an attractive strategy, even though the promising results of experimental models and limited clinical studies need to be confirmed in larger randomized trials. 1. Introduction The intestinal microflora is a complex ecosystem, consisting of more than 500 microbial species, that are involved in the digestion of nutrients and the production of vitamins and short-chain fatty acids; furthermore, the gut microflora plays a role in local immunity, forming a barrier against pathogens, together with the intestinal mucosa [1]. The derangement of the gut microflora and increased microbial translocation (MT) have been widely described in advanced liver disease and associated with the pathogenesis of the complications of cirrhosis [2]; moreover, recent lines of evidence suggest the intestinal microflora to be directly implicated in the induction and progression of liver damage in several chronic liver diseases, including alcoholic and non-alcoholic steatohepatitis, two common causes of cirrhosis [3–5]. Here, we review current concepts regarding the pathogenesis of MT, its role in liver diseases and the potentialities of therapeutic strategies based on the modulation of intestinal flora (i.e. probiotics). 2. Microbial Translocation in Cirrhosis Microbial translocation (MT) is defined as the migration of viable microorganisms or bacterial endotoxins
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