PURPOSE: Burn wound infection, sepsis and organ failure have been major causes of death in massive burn patient. Because it is difficult to fundamentally prevent bacterial colonization by medical treatment, the need of surgical intervention is advocated by many authors. Therefore the effects of early excision and optimal time were studied. METHODS: Twenty four patients with thermal injuries, on whom early excision of eschar was performed, between June and Aug. 2003, were studied. Fascial excision over third and fourth degree burns and tangential excision over indeterminate areas were performed. Superficial and deep layers of eschar was separated and cultivated, and bacterial colony counts performed. The patients were divided into two groups: a colony count equal or greater than 10(5)/g (group A) and less than 10(5)/g (group B), and studied. The plasma endotoxin levels were assayed and compared. RESULTS: Sepsis occurred at a higher rate when the bacterial colony counts were equal or greater than 10(5)/g at the wound site. Bacterial colonization appears to be greatly increased on the 4th in of escharectomy in superficial layers, and on the 5th in deep layers, in old aged or young child patients tends to occur earlier and with greater severity. The microorganism isolated in all patients was Pseudomonas aeruginosa. There was no statistical difference in the plasma endotoxin levels between groups A and B. CONCLUSION: It is suggested that all massive burn injuries would be better treated with early excision, within 3 days after burns, especially in old aged or young child patients.