Probiotic control of diarrhoeal disease.

Probiotics have been suggested to be of use in many diarrhoeal disorders, particularly in the prophylaxis and treatment of infectious diarrhoea. Several different preparations are available commercially and they are widely used but consistent scientific documentation of their efficacy is lacking. Although their putative mode of action is not known, non-pathogenic organisms may prevent or displace enteropathogens from colonising the gut. In vitro studies suggest that some probiotics may exert a direct inhibitory effect on pathogenic organisms. There is some clinical evidence suggesting a possible role for probiotics in the prophylaxis of infectious diarrhoea in some circumstances, but there is little evidence of a beneficial effect in the treatment of established diarrhoea, except in cases of relapsing C. difficile infection. There are no convincing data at present demonstrating efficacy of probiotics in non-infective diarrhoeal disorders. Although the use of probiotics in diarrhoeal diseases is conceptually appealing, their use for this indication is not clearly supported by the available scientific literature at present. Further research into the role of the human microflora in diarrhoeal diseases is needed to aid the selection of appropriate non-pathogenic bacteria for clinical studies. Well conducted controlled clinical trials are then needed in order to determine the place of probiotics in the prevention and treatment of diarrhoeal disorders.