The "three-anti" of the laclobacillus, especially the bifid-bacterium has been well known for a long time. Though the mechanism research in resisting the infection field has achieved great progress in our country, the resistance tumor and the anti-senile research still paused in the animal experiment stage. Through analyzing the animal experiment, the epidemiology investigation and the clinical research result of domestic and external. In the hope that we could have a further understanding of the medical value of the lactic acid fungus products, an outline has been made on the lactic acid fungus prevention and the mechanism of treatment tumor action.