Early in 1962,after an extensive review including 312 cases of bacteremia in burn patients, we were surprised to find that there was about 30% of bacteremia in the patients who had no detectable microorganisms from repeated wound cultures, but blood cultures were usually positive for gut flora. From that time on the idea of gut-origin infection emerged. In following twenty years, a series of experiments were carried on in Wistar rats with 30% TBSA full-thickness burn.The results showed that the fluoresee in labeled enteric microbes (Pseudomonas aeruginosa, Bacteriod fragilis and Candida albicans) could translocate through the stress injured intestinal wall and were recovered in viscera! Organs. The radioisotope 125 Ⅰ labeled endotoxin began to ascend in concentration in portal vein since 15 minutes postbum. Radioauto graphy of liver sections demonstrated the labeled endotoxin granules. With the creation of minute mesenteric lymph fistulas, the clearance of endotoxin and TNFα was found to be significantly high in lymph fluid exited from the intestine. All above evidences indicated that the gut is a potential route of endogenous infection, and it also explained how did the patients menifest sepsis early after burn injury without a definite infectious focus. Now the concepts of gut-origin infection are commonly accepted, the measures like early enteral feeding for the protection of intestinal barrier has been established.