DAO and infection: The plasma DAO activity, serum endotoxin and lactulose to mannitol ratio levels were higher in patients with infection (2.90 ± 1.37 and) than those without infection, but only serum endotoxin (0.33 ± 0.13 vs 0.44 ± 0.21, p = 0.001) was significant higher, the plasma DAO activity (2.90 ± 1.37 vs 4.82 ± 1.57, p = 0.234) and L/M (0.23 ± 0.07 vs 0.34 ± 0.08, p = 0.275) were not significant.