[Probiotics: Is there a scientific basis for their effects?]

Probiotic microorganisms have been used with increasing frequency in nutrition and for therapeutic purposes during the last years. Their application is generally based upon empirical experiences, since their mode of action has been the topic of investigations only recently. It became apparent that probiotics exert a wide spectrum of different effects ranging from direct antagonism against pathogens to influence upon intestinal epithelium and immune system of the host's organism. In this review, the current knowledge is summarized.