Antitumor effect of lactobacilli substances: "L. bulgaricus effect"

Scattered reports suggest a moderate effect, difficult to reproduce, of products from strains of specific lactobacilli (L. bulgaricus) used for yogurt on cancer and leukemia in mice. Skeptics have disregarded that even lyophilized preparations of demonstrated activity will lose effect when stored above -80 degrees C. This explains some inconsistencies of results and difficulties in repetition. Flow DNA fluorometry of ascitic fluid from leukemic mice has shown some accumulation of cells in the G2 + N phase after 8 hours, clearly different from the effect of 5-fluorouracil, although occasionally similar in strength. The effect depends on the strain of lactobacilli, and seems to deserve rational analysis by modern methods.