The aim of the study was to analyse the effects of early enteral feeding on the prevention of enterogenic infection in severely burned patients. A total of 22 patients with severe burns were randomly divided into an early enteral feeding group (EF) and a delayed enteral feeding group (DF). The levels of serum endotoxin and TNF-alpha were dynamically detected in the members of both groups, and two unmetabolized sugars (lactulose and mannitol) were orally administered to these patients 1, 3 and 5 days postburn. Intestinal permeability was evaluated by detecting the concentrations of lactulose and mannitol in the urine and the lactulose-mannitol ratio (L/M) ratio. The levels of serum endotoxin and TNF-alpha in severely burned patients were significantly higher than in normal subjects (P<0.01). The endotoxin level was positively related to the TNF-alpha level (rEF=0.93, P<0.01; rDF=0.80, P<0.05). The urinary lactulose levels in both groups were significantly higher than in normal (P<0.01), the urinary mannitol levels showed no obvious changes (P>0.05). The urinary L/M ratios in both groups were significantly higher than in normal subjects (P<0.01). The urinary L/M ratio was positively related to the serum endotoxin level (r=0.95, P<0.01). The urinary lactulose levels and the urinary L/M ratios in the EF group were significantly lower than in the DF group (P<0.01). The levels of serum endotoxin and TNF-alpha in the EF group were significantly lower than in the DF group (P<0.01). It is suggested that intestinal permeability was markedly higher after burns than normal, and was positively related to the gut-derived endotoxemia. Early enteral feeding may decrease intestinal permeability, preserve the intestinal mucosal barrier and have a beneficial effect on the reduction of enterogenic infection.