Polymorphonuclear leucocyte (PMN) function is suppressed for several weeks after burn injury, rendering patients susceptible to infection, commonly with Staphylococcus aureus. A study was performed to determine the effects of surgery to the burn wound and antimicrobial prophylaxis with teicoplanin on killing of S. aureus by PMNs taken from burn patients. The bactericidal rate was significantly reduced before surgery compared to controls (P<0.01 Mann Whitney), but neither surgery nor teicoplanin had any significant additional effect on the bactericidal rate. The bactericidal rate of PMNs did not have any significant effect on clinical outcome following surgery.