Abstract
Bacteria are present throughout the GI tract but their pattern and concentrations vary greatly. Probiotics are living microorganisms that belong to the normal intestinal flora and are important to the health and well-being of the host. The concept of probiotic therapy is still controversial; there are many data from in vitro and animal studies, however, to date the beneficial effects of probiotics in humans have mostly been demonstrated under poorly defined experimental conditions. Several experimental and clinical observations suggest a role for the intestinal microflora in inflammatory bowel disease (IBD) pathogenesis and there is increasing evidence supporting the potential therapeutic role for probiotics in the treatment of IBD. The use of probiotics to treat GI infections has produced contrasting results; their efficacy in the prevention or treatment of infective diarrhoea was evaluated in a large number of studies; however, the most convincing evidence of their benefit concerns rotavirus infection in children. Future research needs to focus on obtaining more precise information on the composition of the enteric microflora and the mechanisms of action of probiotics.