L. reuteri is a heterofermentative bacterium, and is consid- ered to be one of the few true autochthonous Lactobacillus species in humans and animals. Many researchers have already selected some specific L. reuteri strains isolated from human feces, breast milk, the human vagina, the human oral cavity, guinea pigs, rats, pigs, broilers and sourdough. There is now mounting evidence to show that selected L. reuteri strains have probiotic character- istics, and can provide health benefits to their hosts. We have constructed a summary table (Table 1), in order to provide an overview of the reported L. reuteri strains used as probiotics.